Kiln Wiring

[JoeNorm]

I have a kiln with specs saying it runs at 60amps and asks for an 80amp breaker on #4 wire.

I had already purchased #6 copper wiring for this install, which is good to 65 amps. Do I have to follow the manufactures chart on this? I have heard arguments on whether or not kilns are considered continuous loads.

I am in Washington, where they now allow NM to be used with the 75 deg column.

I am not trying to skimp, but also not trying to delay the job if it is not necessary.

Thanks

 

[tthh]

A kiln will be a continuous load. The thing runs for hours at full rated load.

 

[infinity]

A kiln will be a continuous load. The thing runs for hours at full rated load.

I'm not very familiar with kills but don't they have a thermostat?

 

[SceneryDriver]

I'm not very familiar with kills but don't they have a thermostat?

They do, but they can also take several hours to heat up. I'd certainly consider them a continuous load.


ScerneryDriver

 

[nizak]

I'm not very familiar with kills but don't they have

They do, but they can also take several hours to heat up. I'd certainly consider them a continuous load.


ScerneryDriver

By all means. I’d definitely stay away from wire nuts as any part of the branch circuit connection as well.

 

[tortuga]

I have a kiln with specs saying it runs at 60amps and asks for an 80amp breaker on #4 wire.

I had already purchased #6 copper wiring for this install, which is good to 65 amps. Do I have to follow the manufactures chart on this? I have heard arguments on whether or not kilns are considered continuous loads.

I am in Washington, where they now allow NM to be used with the 75 deg column.

I am not trying to skimp, but also not trying to delay the job if it is not necessary.

Thanks

I have always considered a kiln to be "industrial process heating equipment" and fall under article 425, thus the branch circuit is a continuous load. Kilns employ electric resistance heating elements, and they are used to make stuff. Other than that you have 110.3(B)

 

[infinity]

They do, but they can also take several hours to heat up. I'd certainly consider them a continuous load.


ScerneryDriver

It seems that what's in the instructions also want a continuous load factor added in.

 

[hillbilly1]

A lot of people that have kilns want a buck/ boost transformer to buck it to 208, if you have 240. Makes the expensive elements last longer. Takes longer to heat up though.

 

[infinity]

During normal operation these kilns take over 3 hours to reach the desired temperature?

 

[zbang]

A lot of people that have kilns want a buck/ boost transformer to buck it to 208, if you have 240. Makes the expensive elements last longer. Takes longer to heat up though.

Many kilns are offered in 240 and 208 volt models with different elements, and they're rather robust, not like a lighting filament.

 

[roger]

My wife has a kiln and it definitely runs wide open for long periods.

 

[tortuga]

To me a kiln is process heating (it heats material to change it), and most all pottery/glass kilns that I have seen are resistance-heated,
and so would fall under Article 425, and that requires the branch circuit to be sized as a continuous load.
Seems all UL / NEC sections that deal with resistance heating size the branch circuit conductors at 125% of the load.

 

[infinity]

Even if it didn't meet the definition of a continuous load the instructions would require the 80 amp OCPD for a 60 amp load.

 

[BarryO]

By all means. I’d definitely stay away from wire nuts as any part of the branch circuit connection as well.

And stay away from cheaper receptacles and plugs. Use those "EV rated" ones. Ask me how I know.

 

[hillbilly1]

Many kilns are offered in 240 and 208 volt models with different elements, and they're rather robust, not like a lighting filament.

Every one I’ve put in, they wanted to drop the voltage, apparently the elements are rather expensive. I didn’t on my sister’s, but she has yet to do a firing. And that was about 15 years ago. She just uses the ones at the school she teaches at! LOL! I’m glad because it’s in one of my buildings and on my meter. LOL!

 

[zbang]

The elements aren't that cheap, but the ones I've touched aren't fragile at all. Everything I've read or heard suggests getting at least a couple hundred firings out of a set, and even firing weekly that's over 4 years and a lot of pottery. Plus they won't get as hot; not a problem for some clays but if you're doing stoneware or porcelain it would be.