Chip Richards on fri 17 oct 08
My electrical expertise is close to being maxed out by replacing a light bulb,
but I think I have enough mechanical ability to create my own electrical
"adapter" cord. What I don't have is electrical knowledge, which I'm hoping
someone on the list might have and share. I'd write to Paragon directly, but
I know that Arnold Howard watches this list like a hawk, and I have hope that
the answer might be useful to others as well as to me.
I live in an older house whose clothes dryer outlet is a NEMA 10-30, which
I've heard is not used any more. Part of why it was discontinued is that it
does an odd thing, tailored to clothes dryers and ovens and stoves, which is
to run current through the "ground" wire, and to ground the appliance through
the "neutral" wire. (That's my understanding, which may be goofed up.)
Now, I have a brandy-new Paragon "Biggest Little Kiln", which as far as I can
tell is a TnF82-3 modified with 30-amp elements. It comes with a 6-30 plug.
So my questions are: If I build a cord that just connects hots-to-hots and
ground-to-ground, with a 10-30 plug on one end (plugged into my existing dryer
outlet) and a 6-30 receptacle on the other, will I actually get 240v to the
elements, or does the 10-30 circuit carry only 120v on each "hot"? And/or
will I fry my kiln's controller if I plug it into such a monstrosity?
Mongo no like fire. Okay, Mongo like fire, but only *inside* kiln.
--
Chip
W J Seidl on fri 17 oct 08
Chip:
You've got it _almost_ right . Time for electricity 101.
See the diagram below:
110v (black) \
0v (usually white) neutral > these three make 220
110v (red) / (ok, 240 if each "leg" is
120v not 110v)
The problem with this is that the 0v line (the white)
is not only the neutral but also the ground as you mentioned.
To fix this problem, they added a copper wire (no insulation on it)
that is now used for the"ground" ("earth" if you're European, Asian or
Canadian)
so now we have a four wire system (at least in the US) as follows:
110v (black) \
0v (white) neutral > this makes 220 or 240 (see above)
110v (red) /
ground (green or copper)/ <<not used for neutral EVER
The problem with the added wire is that in a lot of electrical panels
(your circuit breaker or fuse box), there is only one buss bar, to
which ALL the ground and neutral wires (white AND bare copper)
are connected. The new code calls for TWO buss bars, one strictly
for neutral and the other for ground, which has a separate wire
going to a ground rod in the dirt outside. The two cannot be
interconnected, according to code.
The new system is much safer, since the neutral now carries
potential (the "return" voltage you mention), but not ground.
The old system worked for many years without a problem, but
under certain conditions, one could shock themselves on it.
Don't ask me how I know.
Code is different in different parts of the country, but an
electrician would probably hardwire your kiln right to the
screw connections on the dryer outlet,
or remove the outlet and connect the wires to each other
with wire nuts and call it a day.
Assuming you actually NEED that dryer outlet for a dryer,
and plan to plug and unplug the kiln as needed, you might
want to wire the hots to the hots,
use the third leg for your neutral,
and run a separate wire (a ground wire, maybe #10...
it can be a bit lighter since it's not carrying current)
directly from the metal of the dryer outlet (the ground)
to the ground of the kiln, which may be in that plug on
the kiln, or at a ground lug inside the electrical connection
panel on the kiln...there should be a ground lug there.
It might be green in color, or just marked "ground".
Arnold can tell you whether or not this is sound advice, I'm sure.
Just one note of caution...keep an eye on that plug in the
dryer outlet. It can melt down from excessive heat.
There have been other posts about this problem, caused
by the fact that the plug "prongs" depend on friction to
hold them in place and a slightly loose one can cause
arcing inside the outlet...and that's what causes fires, Mongo.
Hope that helps.
Best,
Wayne Seidl
Waite, Maine
Chip Richards wrote:
> My electrical expertise is close to being maxed out by replacing a light bulb,
> but I think I have enough mechanical ability to create my own electrical
> "adapter" cord. What I don't have is electrical knowledge, which I'm hoping
> someone on the list might have and share. I'd write to Paragon directly, but
> I know that Arnold Howard watches this list like a hawk, and I have hope that
> the answer might be useful to others as well as to me.
>
> I live in an older house whose clothes dryer outlet is a NEMA 10-30, which
> I've heard is not used any more. Part of why it was discontinued is that it
> does an odd thing, tailored to clothes dryers and ovens and stoves, which is
> to run current through the "ground" wire, and to ground the appliance through
> the "neutral" wire. (That's my understanding, which may be goofed up.)
>
> Now, I have a brandy-new Paragon "Biggest Little Kiln", which as far as I can
> tell is a TnF82-3 modified with 30-amp elements. It comes with a 6-30 plug.
>
> So my questions are: If I build a cord that just connects hots-to-hots and
> ground-to-ground, with a 10-30 plug on one end (plugged into my existing dryer
> outlet) and a 6-30 receptacle on the other, will I actually get 240v to the
> elements, or does the 10-30 circuit carry only 120v on each "hot"? And/or
> will I fry my kiln's controller if I plug it into such a monstrosity?
>
> Mongo no like fire. Okay, Mongo like fire, but only *inside* kiln.
>
> --
> Chip
>
>
Chip Richards on sat 18 oct 08
On Fri, Oct 17, 2008 at 06:37:26PM -0400, W J Seidl wrote:
> You've got it _almost_ right.
Story of my life.
> Time for electricity 101.
Thanks very much for the reply!
> To fix this problem, they added a copper wire (no insulation on it) that is
> now used for the"ground" ("earth" if you're European, Asian or Canadian) so
> now we have a four wire system (at least in the US) ...
Yes, I've read that most newer houses use a 14-30 (four-wire) connector for
the dryer outlet. And they probably have the split neutral and ground busses
as you described. My house does not, since back in 1971 they were grateful
just to *have* electricity. (Joking--I know the codes back then allowed the
bonding of neutral and ground, so they were just following accepted practice.
And Duncan used to market its leaded clear gloss as food-safe back then, too.)
> The new system is much safer, since the neutral now carries potential (the
> "return" voltage you mention), but not ground. The old system worked for
> many years without a problem, but under certain conditions, one could shock
> themselves on it. Don't ask me how I know.
>
> Code is different in different parts of the country, but an electrician
> would probably hardwire your kiln right to the screw connections on the
> dryer outlet, or remove the outlet and connect the wires to each other with
> wire nuts and call it a day.
I'd love a safer system. I'd love to be able to afford to have an electrician
direct-wire the kiln, since everything I've read here and elsewhere suggests
that's the safest and most reliable setup. Heck, I bought a used 27-inch
Cress last year for really cheap, but haven't had the coin to have a 50-amp
circuit put in to run it, so it sits in my shed, lonely and forlorn. If I
could pay a professional to do the work, I wouldn't have to come here and beg
people to relieve my ignorance.
> Assuming you actually NEED that dryer outlet for a dryer, and plan to plug
> and unplug the kiln as needed ...
I do still need the dryer outlet for the dryer, but am not planning to plug
and unplug. It's much worse than that, but I didn't think it was relevant to
my "conversion" question: I plan to put not only a 6-30 outlet on this
glorified extension cord, but also a 10-30, into which I'll plug the dryer.
And use administrative techniques to avoid running both the kiln and the dryer
at the same time. I mean, what could possibly go wrong with that? ;)
> ... you might want to wire the hots to the hots, use the third leg for your
> neutral, and run a separate wire (a ground wire, maybe #10... it can be a
> bit lighter since it's not carrying current) directly from the metal of the
> dryer outlet (the ground) to the ground of the kiln, which may be in that
> plug on the kiln, or at a ground lug inside the electrical connection panel
> on the kiln...there should be a ground lug there. It might be green in
> color, or just marked "ground".
I don't entirely follow this. The kiln has a 3-wire plug, and seems to be
happy being grounded through the third pin of that connector. Same with the
dryer. You're suggesting that I should separately ground the kiln?
And from your diagrams and explanation, it sounds like my original plan will
actually work, since the 3-wire 10-30 and 6-30 connectors really aren't any
different electrically. But as good as I am with 3D graphics, Unix utilities,
and compiler internals, electricity is still a bit of a mystery to me, a magic
beast that can be controlled but is always looking for a chance to attack.
One thing that concerns me: You suggest 10 gauge wire for the "lighter"
ground, but I was told that 10 is what I should use for the (240v) power
wires. I bought a length of cord with three 10-gauge braided copper wires in
it, looks like you could tow an ocean liner with it. Should I use something
thicker, like 8ga? Or is "#10" not the same as "10 gauge"?
> Arnold can tell you whether or not this is sound advice, I'm sure.
I'm hoping. I do like the idea of having everything well and separately
grounded, but am uncertain about the particulars in relation to the three-wire
circuit that's already in place in this house, and on both appliances. I'll
check for a grounding lug on the kiln, at least.
> Just one note of caution...keep an eye on that plug in the dryer outlet. It
> can melt down from excessive heat. There have been other posts about this
> problem, caused by the fact that the plug "prongs" depend on friction to
> hold them in place and a slightly loose one can cause arcing inside the
> outlet...and that's what causes fires, Mongo.
Yes, good advice, and I've always inspected the plugs of my kilns after every
two or three firings, just to make sure nothing is going downhill. I actually
did catch one that was showing a little darkening, leading me to relocate it,
after which it has shown no changes. Scary stuff, at least for me. My
"Y-connection" cabling plan is intended to avoid stressing the plugs by
constant insertion and removal, but that still doesn't make inspection
unnecessary.
> Hope that helps.
Very enlightening (no pun intended), thank you!
--
Chip
Taylor Hendrix on sat 18 oct 08
Chip:
I'm going to suggest that you don't follow through with your plans.
Let me explain my objections.
You are planning on creating a plug harness that would place two
pieces of equipment onto one circuit. The combined amperage of that
equipment exceeds the current safe load for that circuit. BTW, you
have not told us the amperage of your dryer circuit, so I'm guessing
30 amps perhaps.
When you piece together an extension cord you are creating wire
junctions that could potentially loosen causing heat. You better be
sure of your wiring chops if you are going to fabricate a connection
like you are proposing. Remember you are going to be plugging it in
and leaving it alone. You will still have to inspect every connection
in your harness. Is it better than an alternative? You planning on
doubling up wires in the wall plug? Can the plug accommodate all the
wire? No? You going to just splice wires then?
According to the Paragon information I have been able to find, that
kiln of yours is a 30 amp kiln but Paragon requires a 50 amp breaker.
50 amp circuits require heavier wire (#6) than 30 amp circuits. You
will need to ask Paragon why they up the breaker for their kilns, but
I believe it is a safety measure to insure the circuit is not taxed to
100% capacity. So running it on a 30 amp circuit is a bit dicey from
the get go.
If it is your house, you need to invest in your house and at the least
replace the dryer circuit with the upgraded wire. If you feel
comfortable rigging up a homemade extension cord for 220 than you
should not feel intimidated rewiring the circuit yourself. You can do
all the grunt work and have a professional electrician make the final
hookup to the box. You can do it.
I'm making the assumption that you are not relying on clay as your
sole means of support. Don't shortchange your #1 investment for a
hobby fix if you indeed do own the house. I don't believe it is worth
it.
I for one would stick with a factory plug set and plug each device
into the wall plug for use rather than cobble together a potentially
dangerous system. It will keep the area need and free of vulnerable
cord splices. If you are careful when you plug and unplug you should
not wear out the wall plug unduly. Of course that doesn't help you
with your older wall socket problem.
Remember too that the Paragon kiln draws a little energy even when not
firing, so you will need to at least run the numbers on your makeshift
extension cord to insure it can handle running the dryer and
delivering whatever to the kiln controller. Be sure to check and see
if the breaker is old. Won't want that thing to fail to open if for
some crazy reason your administrative fail safe ...er...fails and both
the kiln and the dryer are turned on.
Just my thoughts, bro,
Taylor, in Rockport TX
The Fuzzy Chef on sat 18 oct 08
Wayne,
> 110v (black) \
> 0v (white) neutral > this makes 220 or 240 (see above)
> 110v (red) /
> ground (green or copper)/ <<> not used for neutral EVER
This reminds me. The last time I had to re-wire my Paragon kiln* I
noticed that the 220 seems to split when it enters the kiln into two 110
lines, each powering half the coils.
It seems like, absent good 220 locally, that a 4-prong kiln could
theoretically be powered by two high-amp 110 circuits. Since this isn't
done, though, there must be some reason for it ... why?
--Fuzzy
* = not really as hard as it sounds, just patience-testing. An electric
kiln is really a very simple device wiring-wise. But: get a good
voltage tester, and make sure that when you test segments they're not
falsely grounding through the kiln outer steel.
Taylor Hendrix on sat 18 oct 08
Fuzzy:
In actuality any 220 device in your house is being powered with just
two 110 legs. Residential supply in the US anyway is 2 110 lines and
one neutral. When you wire up a 220 breaker and plug it in, it
actually makes connection with both hot legs inside your load center.
One wire from the breaker (black) gets one 110 leg and the other wire
(red, perhaps) gets the other.
The reason that you don't really want to hook a kiln up to two 110
breakers is, you don't want to have to remember to throw TWO switches
to cut all the power. There are probably other reasons for other 220
equipment, but that is a basic consideration.
Most houses don't have really large 110 circuits. I've wired many 20A
circuits with #12 wire, but nothing bigger in a 110. Not many 110/50A
devices in the home. I could be wrong on this but I don't think so. A
window A/C unit can be one. Thus the need for both legs to lighten the
load on a single conductor. To borrow a current trope: spread the
wealth (pun and political illusion intended).
If you take a look at a typical 220 GE breaker you will see it looks
like two 110 breakers joined at the hip (and throw switch). Both legs
are killed with the flip of one switch. I still need to get a
replacement breaker for my small water heater. Right now it is on two
breakers side by side. Not the best solution.
Taylor, in Rockport TX
On Sat, Oct 18, 2008 at 2:13 PM, The Fuzzy Chef wrote:
> Wayne,
>
>> 110v (black) \
>> 0v (white) neutral > this makes 220 or 240 (see above)
>> 110v (red) /
>> ground (green or copper)/ <<>> not used for neutral EVER
>
> This reminds me. The last time I had to re-wire my Paragon kiln* I
> noticed that the 220 seems to split when it enters the kiln into two 110
> lines, each powering half the coils.
>
> It seems like, absent good 220 locally, that a 4-prong kiln could
> theoretically be powered by two high-amp 110 circuits. Since this isn't
> done, though, there must be some reason for it ... why?
>
> --Fuzzy
>
> * = not really as hard as it sounds, just patience-testing. An electric
> kiln is really a very simple device wiring-wise. But: get a good
> voltage tester, and make sure that when you test segments they're not
> falsely grounding through the kiln outer steel.
>
--
Taylor, in Rockport TX
wirerabbit1 on Skype (-0500 UTC)
http://wirerabbit.blogspot.com
http://wirerabbitpots.blogspot.com
http://www.flickr.com/photos/wirerabbit/
Chip Richards on sat 18 oct 08
On Sat, Oct 18, 2008 at 11:39:46AM -0500, Taylor Hendrix wrote:
> I'm going to suggest that you don't follow through with your plans.
I appreciate your concern.
> You are planning on creating a plug harness that would place two pieces of
> equipment onto one circuit. The combined amperage of that equipment exceeds
> the current safe load for that circuit.
That's true, which is why I won't be running both appliances (which are in the
same room) at the same time.
> BTW, you have not told us the amperage of your dryer circuit, so I'm
> guessing 30 amps perhaps.
It has a 30-amp breaker, so I assume it's wired to carry 30 amps.
> When you piece together an extension cord you are creating wire junctions
> that could potentially loosen causing heat. You better be sure of your
> wiring chops if you are going to fabricate a connection like you are
> proposing.
The connectors in these plugs seem pretty straightforward, but you're right,
any given junction could start out faulty, or go bad later.
> Remember you are going to be plugging it in and leaving it alone. You will
> still have to inspect every connection in your harness.
I do plan to inspect the setup regularly, just as I do with all kiln
connections. I admit, I haven't inspected the dryer connection in years, but
I don't worry that much about it, nor about the other outlets in the house,
except the ones I have "special" things like kilns plugged into.
> Is it better than an alternative?
The way I see it right now, the alternative is to not run the kiln.
> You planning on doubling up wires in the wall plug? Can the plug accommodate
> all the wire? No? You going to just splice wires then?
I'm planning to run the wires through the 10-30 receptacle and on to the 6-30
receptacle. Won't touch the wall socket. I've checked the receptacle housing
and connectors, and they seem up to the task, at least physically.
> According to the Paragon information I have been able to find, that
> kiln of yours is a 30 amp kiln but Paragon requires a 50 amp breaker.
The TnF82 series is indeed a 30-amp kiln for which Paragon recommends a 50-amp
breaker. However, the kiln I have isn't a stock TnF82 ... it's a slightly
modified version:
http://www.bigceramicstore.com/Supplies/kilns/BCSBLKKiln.htm
I assume they put downsized elements in it, because it's rated at 28 amps, and
while it's pushing things a bit to put it on a 30-amp circuit, that's how they
advertise it. If I have frequent breaker trips (in my book, that's one or
more), or abnormal heating in the wires, I'll have to reevaluate the setup.
> 50 amp circuits require heavier wire (#6) than 30 amp circuits. You
> will need to ask Paragon why they up the breaker for their kilns, but
> I believe it is a safety measure to insure the circuit is not taxed to
> 100% capacity. So running it on a 30 amp circuit is a bit dicey from
> the get go.
Right, if it were a standard TnF82. The Cress I bought last year (a B27HT, as
I recall) has a 50-amp plug on it, and the lady I bought it from was running
it on a 50-amp breaker. However, it's rated at 48 amps, and prudence would
dictate using a 60-amp circuit for it, as well as having it directly wired
instead of using a 6-50 wall plug. In an ideal world, I would have this new
Paragon professionally direct-connected to a 50-amp circuit. Sadly, this is
not an ideal world.
> If it is your house, you need to invest in your house and at the least
> replace the dryer circuit with the upgraded wire.
Send me a check and I'll be glad to. I called electricians for estimates,
and found that even the cheapest was out of my price range.
> If you feel comfortable rigging up a homemade extension cord for 220 than
> you should not feel intimidated rewiring the circuit yourself. You can do
> all the grunt work and have a professional electrician make the final hookup
> to the box. You can do it.
Sez you. To me they seem an order of magnitude different in effort and skill
required.
> I'm making the assumption that you are not relying on clay as your sole
> means of support. Don't shortchange your #1 investment for a hobby fix if
> you indeed do own the house. I don't believe it is worth it.
My money situation is complicated, starting with my job being shipped to India
earlier this year. No, I'm not a professional potter, nor do I expect to make
a living entirely with clay any time soon. But having this kiln is part of my
financial planning, and I'll be in a bit of a pickle if I can't run it. Yes,
your unspoken comment that I'd be in a pickle if the house burned down is also
true. Especially if I went with it.
> I for one would stick with a factory plug set and plug each device into the
> wall plug for use rather than cobble together a potentially dangerous
> system.
That's why I'm out here asking for advice--so I don't "cobble together"
something that's "potentially dangerous". What I hope to do is fabricate a
unit that's acceptably safe, even if it is homemade. I'm using all UL-listed
parts, not just twisting bare wires together and hoping it works.
> It will keep the area need and free of vulnerable cord splices. If you are
> careful when you plug and unplug you should not wear out the wall plug
> unduly. Of course that doesn't help you with your older wall socket problem.
No, that really doesn't address the problem at all. If I had a 6-30 wall
socket already, I wouldn't be asking.
> Remember too that the Paragon kiln draws a little energy even when not
> firing, so you will need to at least run the numbers on your makeshift
> extension cord to insure it can handle running the dryer and delivering
> whatever to the kiln controller.
Makeshift? Cobbled together? You really have a picture of me as an
incomptetent, doncha? Just because I'm soft in the area of electrical
wiring doesn't mean I'm a fumble-thumbed risk-taking fool, honest.
> Be sure to check and see if the breaker is old. Won't want that thing to
> fail to open if for some crazy reason your administrative fail safe
> ...er...fails and both the kiln and the dryer are turned on.
Good lord, man, the whole house is old. I have no reason to think that the
breakers have been touched since the place was first erected. I had sorta
planned to test it by firing up the dryer while the kiln is on, under
controlled conditions. If the breaker doesn't trip, it will need some
attention, although that lone test wouldn't be entirely probative.
> Just my thoughts, bro,
I appreciate your input, and your points are well made. I may have given the
impression that I've never twisted a screw before, but that's not quite the
case. I am just not familiar with the specifics of 240v household circuits,
and was hoping to get some data from someone who is.
--
Chip
Chip Richards on sun 19 oct 08
On Sun, Oct 19, 2008 at 04:20:14PM -0500, Taylor Hendrix wrote:
> If you are uncomfortable pulling a new circuit for your dryer, I
> understand. But you are wrong in your evaluation of the difficulty. In my
> estimation, if you can successfully wire a duplex plug or a dryer plug, you
> can make the connections required for a circuit.
Actually, making the connections is not the part that bothers me. Once I
throw the main breaker, I'm bold enough to stick my (gloved) fingers into just
about any wires in the house, even behind the Mysterious-Beast-Deflecting
inner panel in the breaker box. What worries me is getting the wire from one
end of this flat-roofed house (where the breaker box is) to the other (where
the kiln will be). These little slump-block crackerboxes were not intended
for easy modification or upgrade. I've pulled enough coax, thin-net, and
Cat-5 network cable to know that pulling wires is something I *really* want to
avoid.
> You are already having to buy the wire for your little project, and that
> wire will be pretty much useless once you finally upgrade on down the road.
Before I upgrade, I'm going to be moving to a different house, one far enough
out of the heart of the city so I can start making disastrous mistakes with
fuel kilns. And I'll be looking for a place where a shadetree mechanic can
actually do things to the property without calling in the Guild of Calamitous
Contracting. Not that I have anything against licensed contractors, it's just
that I do prefer to have some degree of knowledge of and control over my
surroundings.
> Take some time, save up enough clams to make a #8 run from your box to where
> you want the kiln.
To save clams you have to have clams coming in. Right now that's, erm, a
problem.
> If you have space in your breaker box, this is really the thing to do.
I have one "dual" slot left in it, but right now I'm wondering if it's like
having checks in your checkbook--doesn't necessarily mean there's money in the
account. I would have to verify thoroughly whether the main breaker can
handle an extra 40 or 50 amps; I suspect it really can't. People in these
houses were supposed to have cocktail parties, not fire stoneware.
> You'll feel so good that you did this yourself...for your pottery. You
> and nobody else. Just you and some good electrical books.
Oh, I fully understand that feeling. I've rebuilt motors, constructed
furniture, done minor wiring and electrical installation, tons of network
cabling, plumbing, etc., and nothing is quite as satisfying as standing back
and seeing it work, and *knowing* every part and action that went into it.
> I still think running the two plugs in series is unwise, but you're the
> boss.
Frankly, I'm not thrilled with the arrangement myself, but short of installing
a new circuit, I don't see a better alternative. I don't know of any major
roadblock flaws in the plan, it just seems a little squirrelly to me. You can
bet I'll be keeping an eagle eye on it for the first several firings.
> If I had the money for gas, I would come up there and help you put the new
> circuit in. No lie. Damn, the things we do for the love of clay.
I've read a lot of your stuff on this list, and I believe you'd do it. And I
really appreciate the sentiment.
> Pot on brother,
And you as well, sir.
--
Chip
W J Seidl on sun 19 oct 08
Taylor:
Quit wasting money.
Put that heater on a timer. Use an Intermatic T104 (about $55)
and cut your usage down to 8 hours a day, not 24.
(5-8AM for showers and dishes), 11AM-1PM (more dishes for lunch and
laundry) 5-8PM (more laundry and showers)
That will put about $20/month back into your pocket (at 0.12/KwH).
Also, any decent electrical supply can sell you a "bridge" (about $1.49,
maybe less)
to slip on over those two switch toggles to make two separate breakers
into "one" double pole.
$20/month buys a lot of chicken feed.
Best,
Wayne Seidl
Taylor Hendrix wrote:
> Fuzzy:
>
> In actuality any 220 device in your house is being powered with just
> two 110 legs. Residential supply in the US anyway is 2 110 lines and
> one neutral. When you wire up a 220 breaker and plug it in, it
> actually makes connection with both hot legs inside your load center.
> One wire from the breaker (black) gets one 110 leg and the other wire
> (red, perhaps) gets the other.
>
> The reason that you don't really want to hook a kiln up to two 110
> breakers is, you don't want to have to remember to throw TWO switches
> to cut all the power. There are probably other reasons for other 220
> equipment, but that is a basic consideration.
>
> Most houses don't have really large 110 circuits. I've wired many 20A
> circuits with #12 wire, but nothing bigger in a 110. Not many 110/50A
> devices in the home. I could be wrong on this but I don't think so. A
> window A/C unit can be one. Thus the need for both legs to lighten the
> load on a single conductor. To borrow a current trope: spread the
> wealth (pun and political illusion intended).
>
> If you take a look at a typical 220 GE breaker you will see it looks
> like two 110 breakers joined at the hip (and throw switch). Both legs
> are killed with the flip of one switch. I still need to get a
> replacement breaker for my small water heater. Right now it is on two
> breakers side by side. Not the best solution.
>
> Taylor, in Rockport TX
>
> --
> Taylor, in Rockport TX
> wirerabbit1 on Skype (-0500 UTC)
> http://wirerabbit.blogspot.com
> http://wirerabbitpots.blogspot.com
> http://www.flickr.com/photos/wirerabbit/
>
>
Karin Givon on sun 19 oct 08
Michael--
I have a question that has been simmering in the back of my mind. I
use a long long extension cord, have for 30 years. It does not get
warm or hot when I fire. But the cord from my new Scutt electronic
lala kiln gets quite warm. Should I be concerned about it? Not hot,
but quite warm.
Any info would be most welcome.
\thanks,
Karin again
Nevada CIty, CA
W J Seidl on sun 19 oct 08
Chip:
#10 wire (or ten gauge, depending on who you're speaking to)
either stranded or solid conductor is only good for about 20 amps,
(assuming THHN insulation, conduit installation, and other peripheral
factors.)
Don't use it for anything of a higher amperage...you're just _asking_
for a fire.
Ask any electrician in your area...just go down to the local electrical
supply or
the wire aisle of Home Depot and ask one of the guys there. They'll tell
you.
I'm running a 50 amp service to my garage here, using #6
My dryer is wired with #8. I ran #4 to my kiln, but it draws a max of 75
amps.
As I said before, codes vary, but you can only push just so much current
through a wire
before it starts heating up...the basis for the operation of your
toaster .
Home Depot (I think, still) sells a little yellow covered spiral bound book
(with red cover lettering) called "The Ugly Book". It gives all that
info such as how many of what size
wires you can put into what size conduit, how far you can run a feed,
what size wire for what amp load, etc.
You should pick up a copy. You'll use it forever, and it's amazing what
you'll learn from reading it.
Last I knew, they sold for $14.99. Much cheaper than a fire .
Best,
Wayne Seidl
Chip Richards wrote:
> One thing that concerns me: You suggest 10 gauge wire for the "lighter"
> ground, but I was told that 10 is what I should use for the (240v) power
> wires. I bought a length of cord with three 10-gauge braided copper wires in
> it, looks like you could tow an ocean liner with it. Should I use something
> thicker, like 8ga? Or is "#10" not the same as "10 gauge"?
>
>
Michael Wendt on sun 19 oct 08
No matter how you feel about Home Depot,
go there and get a copy of :
Wiring Simplified
by Richter.
It explains how to do code legal
wiring yourself.
The National Electrical Code
REQUIRES you to use conductors
rated at 125% of the name plate values
for continuous load devices like kilns.
Wire sizes carry certain ratings...
14 ga. = 15 amps
12 ga. = 20 amps
10 ga. = 30 amps
8 ga. = 40 amps
6 ga. = 50 amps
...
and so on.
a 30 amp kiln REQUIRES a 40 amp
breaker and 8 ga. wire. Heavier if the
run is long. Check the chart for distance
compensation.
Using too light a breaker leads to frequent
trip conditions and breakers don't last long
under these conditions. Use the wire rated
breaker.
Also be aware that wire in free air can
safely carry more current than wire that
is in conduit or embedded in an insulated
wall so consider at least using surface
mounted metal conduit since is will run
cooler than plastic conduit or embedded wire.
Be safe, cheaper is a false economy.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
Chip Richards on sun 19 oct 08
On Sun, Oct 19, 2008 at 09:10:55AM -0700, Michael Wendt wrote:
> No matter how you feel about Home Depot, go there and get a copy of : Wiring
> Simplified by Richter. It explains how to do code legal wiring yourself.
Thanks, Michael and Wayne for your replies. In fact, it was the guy at Home
Depot who told me to get #10 wire for my application, even knowing it was a
kiln I was trying to wire up. I guess he didn't fully understand that meant
"continuous load". From what I've been reading, #10 wire is fine for clothes
dryers, but wouldn't be so great for a kiln. So I'll go buy a length of #8
and chalk it up to learning. I can always use the #10 cord if I want to tow
an ocean liner. ;)
BTW, the run we're talking about here is eight feet, so I don't think there's
a problem using #8 for that.
> The National Electrical Code REQUIRES you to use conductors rated at 125% of
> the name plate values for continuous load devices like kilns. ... a 30 amp
> kiln REQUIRES a 40 amp breaker and 8 ga. wire.
Based on this, I'm screwed, and Big Ceramic Store is advising people to create
unsafe installations. Their whole sales pitch is, "So we asked Paragon to
build us the largest kiln possible that could reach cone 8 and still operate
on a 240 volt, 30 amp circuit." The kiln is rated at 28 amps, so per the
above code it would require at least a 35-amp breaker. (Although as far as I
know 50 amps is the next bigger size above 30, no? I don't recall ever seeing
a 40-amp breaker for sale anywhere.) Was I suckered into buying something I
can't safely use?
> Using too light a breaker leads to frequent trip conditions and breakers
> don't last long under these conditions. Use the wire rated breaker.
If it trips the breaker even once, as far as I'm concerned the setup is unsafe
and I'll need to re-think the whole ... well, the whole rest of my life, I
guess. At least the next six or eight months. Okay, maybe the next three or
four weeks. It'd piss me off, anyway.
> Also be aware that wire in free air can safely carry more current than wire
> that is in conduit or embedded in an insulated wall so consider at least
> using surface mounted metal conduit since is will run cooler than plastic
> conduit or embedded wire.
Yeah, hadn't planned to embed it in the wall. The walls of this room are
cinder block and slump block, so that really isn't an option anyway.
> Be safe, cheaper is a false economy.
I couldn't agree more.
--
Chip
Taylor Hendrix on sun 19 oct 08
Chip:
If you are uncomfortable pulling a new circuit for your dryer, I
understand. But you are wrong in your evaluation of the difficulty. In
my estimation, if you can successfully wire a duplex plug or a dryer
plug, you can make the connections required for a circuit. Now,
pulling #8 wire might be a bit of a chore but if you want to save
quite a few bucks and have an updated or new circuit, you'll think
about it. You are already having to buy the wire for your little
project, and that wire will be pretty much useless once you finally
upgrade on down the road. Take some time, save up enough clams to make
a #8 run from your box to where you want the kiln.
If you have space in your breaker box, this is really the thing to do.
You'll feel so good that you did this yourself...for your pottery. You
and nobody else. Just you and some good electrical books.
I still think running the two plugs in series is unwise, but you're
the boss. If I had the money for gas, I would come up there and help
you put the new circuit in. No lie. Damn, the things we do for the
love of clay.
Pot on brother,
Taylor, in Rockport TX
Michael Wendt on mon 20 oct 08
Karin,
You can use a thermometer to take its temperature.
Most electrical cable has a listing for operational
temperature stamped right on it. As long as you
stay within the listed values, the Underwriters
Laboratories tests that gave those values indicate
it is safe.
For the record, electrical appliances and wiring
all put out a lot of heat. Just check the temperature
of an electric motor operating at full load. You
need an oven thermometer, its too hot to touch,
so a cord being warm to the touch (not hot or
starting to make a funny smell) is fine usually.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave.
Lewiston, Id 83501
U.S.A.
208-746-3724
wendtpot@lewiston.com
http://www.wendtpottery.com
http://UniquePorcelainDesigns.com
Karin wrote:
Michael--
I have a question that has been simmering in the back
of my mind. I
use a long long extension cord, have for 30 years. It
does not get
warm or hot when I fire. But the cord from my new Scutt
electronic
lala kiln gets quite warm. Should I be concerned about
it? Not hot,
but quite warm.
Any info would be most welcome.
\thanks,
Karin again
Nevada CIty, CA
Arnold Howard on mon 20 oct 08
From: "The Fuzzy Chef"
> This reminds me. The last time I had to re-wire my
> Paragon kiln* I
> noticed that the 220 seems to split when it enters the
> kiln into two 110
> lines, each powering half the coils.
>
> It seems like, absent good 220 locally, that a 4-prong
> kiln could
> theoretically be powered by two high-amp 110 circuits.
> Since this isn't
> done, though, there must be some reason for it ... why?
The kiln you are describing is the earlier Paragon A-series,
which required a 4-wire circuit. We later changed the design
to a 3-wire system with infinite control switches.
The A-series kilns required a 4-wire system because the
neutral wire carried current when the switches were on Low
and Medium. Elements were powered with 120 volts on Low and
Medium. The fourth wire was the safety grounding wire.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
Arnold Howard on mon 20 oct 08
From: "Chip Richards"
Their whole sales pitch is, "So we asked Paragon to
> build us the largest kiln possible that could reach cone 8
> and still operate
> on a 240 volt, 30 amp circuit." The kiln is rated at 28
> amps, so per the
> above code it would require at least a 35-amp breaker.
Chip, your kiln should operate without problems with a
30-amp breaker. It depends on the condition of the breaker.
They wear out with age.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
Arnold Howard on mon 20 oct 08
From: "Chip Richards"
> Now, I have a brandy-new Paragon "Biggest Little Kiln",
> which as far as I can
> tell is a TnF82-3 modified with 30-amp elements. It comes
> with a 6-30 plug.
>
> So my questions are: If I build a cord that just connects
> hots-to-hots and
> ground-to-ground, with a 10-30 plug on one end (plugged
> into my existing dryer
> outlet) and a 6-30 receptacle on the other, will I
> actually get 240v to the
> elements, or does the 10-30 circuit carry only 120v on
> each "hot"?
Chip, thanks for buying the kiln.
Your 10-30 outlet is for a 3-wire, 30 amp circuit. Your kiln
has a 6-30 cord plug also designed for a 3-wire, 30 amp
circuit. We are not allowed to put a 10-30 plug on a kiln.
It has to be 6-30. Nevertheless, your kiln would fire safely
on the 10-30 outlet since the kiln's neutral wire does not
carry current. We use the neutral on that kiln only as a
safety grounding wire.
Yes, you could make a 10-30 to 6-30 adaptor. The main
concern is that the circuit is wired with the correct gauge
wire and that the wall outlet is in good condition. From
your posts, you sound safety conscious. You monitor the kiln
during firing, which kiln manufacturers love to hear.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
The Fuzzy Chef on tue 21 oct 08
Michael Wendt wrote:
> No matter how you feel about Home Depot,
> go there and get a copy of :
> Wiring Simplified
> by Richter.
You could also order this from your local bookstore. Home Depot isn't
the only way to get it.
Personally, I wouldn't wire anything which was 30 amps without at least
an inspection from a professional electrician. You can burn down your
house in an amazingly short time through an electrical fire. And where
I am, the inspection would cost as much as having the electrician do the
wiring.
--Josh
Arnold Howard on tue 21 oct 08
From: "The Fuzzy Chef"
And where
> I am, the inspection would cost as much as having the
> electrician do the
> wiring.
Some communities will inspect wiring done by homeowners. You
first have to go to city hall to take a written test on
basic National Electric Code theory before getting
permission to do the wiring.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
Dan Pfeiffer on tue 21 oct 08
Almost all house fires are said to be caused by bad wiring at least in
Huntsville and all had to get inspected and very very few are done by other
than "professional electricians". Some of the worst wiring I have ever seen
has been done by "Professional" types. That said I have also seen some very
good work done by both professional and non professional. There was a move
to get the city liable for the inspection the city required but that did not
go far. In all too many cases the inspector drives to the site fills out the
paperwork and never looks at the work.
Dan & Laurel
>>>>
Personally, I wouldn't wire anything which was 30 amps without at least
an inspection from a professional electrician. You can burn down your
house in an amazingly short time through an electrical fire. And where
I am, the inspection would cost as much as having the electrician do the
wiring.>>>
Josh Berkus on tue 21 oct 08
Arnold,
> The kiln you are describing is the earlier Paragon A-series,
> which required a 4-wire circuit. We later changed the design
> to a 3-wire system with infinite control switches.
Oh, yeah, this kiln is at least 12 years old, probably more. I like it a
lot; too bad it's stuck in my studio in Oregon, which I only visit 4 weeks
a year. Moving it to CA would probably kill it, though, and I don't have
the wiring for it here.
Since the shop is 4-wire, though, the design is perfect for me.
> The A-series kilns required a 4-wire system because the
> neutral wire carried current when the switches were on Low
> and Medium. Elements were powered with 120 volts on Low and
> Medium. The fourth wire was the safety grounding wire.
Yeah, we discovered that we could merge the neutral and ground when I
hooked it up to a kiln controller with 3 prongs (we had to wire our own
adapters -- using 8-gauge wire!).
So when the kiln goes to high it uses 240 on *each* input? I'm not clear
on how it does that since after the two live wires go into the kiln, they
separate and never come back together. Maybe I'm confused about how 240V
works.
(the main reason I'm asking is that I'm wondering if it would be
theoretically possible to build a kiln which used two 120V 30a circuits
and reach Cone 6)
--
Josh Berkus
San Francisco
Arnold Howard on wed 22 oct 08
From: "Josh Berkus"
> Yeah, we discovered that we could merge the neutral and
> ground when I
> hooked it up to a kiln controller with 3 prongs (we had to
> wire our own
> adapters -- using 8-gauge wire!).
>
> So when the kiln goes to high it uses 240 on *each* input?
Josh, I'm not sure the kiln you have is a Paragon A-series.
If your kiln is only 12 years old, it is an S-series. The
A-series requires a 4-wire circuit; the S-series requires a
3-wire circuit.
Many years ago when we manufactured the A-series, we had a
kiln maintenance slide show.
One of the slides was of a 240 volt wall outlet with the
cover removed. Inside was a short piece of wire that
connected the line neutral and the grounding terminals. At
the time electricians were using that technique to install a
4-wire outlet on a 3-wire circuit. We included the slide to
teach people what not to do.
The A-series kilns will operate on a 3-wire system, but
eliminating the grounding wire is unsafe.
The 4-way rotary switch operates on both 120 and 240 volts.
On Low and Medium, it reduces power by running the elements
on 120 volts.
The infinite control switch operates on 240 volts. It
reduces the power by cycling the elements on and off instead
of by powering the elements on 120 volts.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
The Fuzzy Chef on wed 22 oct 08
Arnold,
> Josh, I'm not sure the kiln you have is a Paragon A-series.
> If your kiln is only 12 years old, it is an S-series. The
> A-series requires a 4-wire circuit; the S-series requires a
> 3-wire circuit.
Well, it may be more than 12 years old, but not more than 20.
However, I suspect that what I have is an S-series rewired for a 4-prong
outlet, since in the switchbox the ground and the neutral are joined.
I can't testify as to how the coils draw power, not having thought to
observe it. Howerver, it certainly seems like the coils are at lower
power for low/medium.
Since that kiln is at my other studio in Oregon, I'll have to wait until
I can take a look and I'll maybe ping you then.
--Josh Berkus
Earl Krueger on wed 22 oct 08
For anyone contemplating doing any electrical work
I would suggest you obtain a copy of the book:
"Wiring a House"
by Rex Cauldwell,
publisher Taunton Direct,
ISBN 978-1-56158-942-5
This is the best book I have ever seen in explaining
how your home electrical system works and how
to make modifications to it. And, it does it in terms
most everyone should be able to understand.
Even if you are not going to do the work yourself
reading through this book will help you in determining
if the electrician you hire knows what they are doing
or not.
At $24.95 it is cheap insurance.
I have no vested interest in this book, the author nor
the publisher. I only recommend it because I think
it is good.
Earl
Elmira, Oregon, usa
Anita Rickenberg on wed 22 oct 08
After hiring two licensed electricians and having both do work that was =
not
to code, I bought 3 electrical wiring books and do all my wiring myself. =
If
I read the instructions and specs in the 1st book, and understand
completely, fine, if not, then on to books 2 and 3. I never start =
working
on a project until I'm sure I completely understand. Similar to what =
Mel
said--I've had contractors comment on how well my wiring was done. My
response is that I don't know enough to cut corners.
Anita
Almost all house fires are said to be caused by bad wiring at least in
Huntsville and all had to get inspected and very very few are done by =
other
than "professional electricians". Some of the worst wiring I have ever =
seen
has been done by "Professional" types. That said I have also seen some =
very
good work done by both professional and non professional. There was a =
move
to get the city liable for the inspection the city required but that did =
not
go far. In all too many cases the inspector drives to the site fills out =
the
paperwork and never looks at the work.
Dan & Laurel
>>>>
Personally, I wouldn't wire anything which was 30 amps without at least =
an
inspection from a professional electrician. You can burn down your =
house in
an amazingly short time through an electrical fire. And where I am, the
inspection would cost as much as having the electrician do the =
wiring.>>>
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