Skutt kiln KMT-614 -3

[ramsy]

I wouldn’t consider a kiln a continuous load. The heating element is either cycled or otherwise limited to control the ramp up time.

Thermostat controlled water heater tanks also cycle on & off, yet are considered a continuous load. Same with 220.82(C)(6) HVAC loads.

220.14(A) may consider it nameplate, until the listed instructions, however poorly written, recommend 30A breaker or wire. NEC 110.3(B) requires the 30A circuit, regardless of continuous load, voltage drop, or other speculation.

 

[don_resqcapt19]

Thermostat controlled water heater tanks also cycle on & off, yet are considered a continuous load. Same with 220.82(C)(6) HVAC loads.

220.14(A) may consider it nameplate, until the listed instructions, however poorly written, recommend 30A breaker or wire. NEC 110.3(B) requires the 30A circuit, regardless of continuous load, voltage drop, or other speculation.

110.3(B) only applies to listing and labeling requirements, not to manufacturer's recommendations.

 

[ramsy]

110.3(B) only applies to listing and labeling requirements, not to manufacturer's recommendations.

OP describes the specs in post #1, as internet recommendations in post #9.

Did not realize listed equipment recommendations, published by manufacturer, are not 110.3(B) instructions?

 

[don_resqcapt19]

OP describes the specs in post #1, as internet recommendations in post #9.

Did not realize listed equipment recommendations, published by manufacturer, are not 110.3(B) instructions?

Only the instructions that are part of the actual listing and labeling. Recommendations are never instructions or requirements, they are simply suggestions. The difference between "shall" and "should" in code language.

 

[retirede]

That would get a red tag from me based on the code rules.

Does that mean he could install 2 (or more) 5-20 receptacles on a 30A circuit?

 

[zbang]

I wouldn’t consider a kiln a continuous load. The heating element is either cycled or otherwise limited to control the ramp up time.

This kiln might not be, but many older ones run the elements continuously until the target heat (cone) is reached, and that can be 12+ hours.

 

[hbiss]

This kiln might not be, but many older ones run the elements continuously until the target heat (cone) is reached,

I can't imagine why the elements wouldn't run continuously with that kind of control.

-Hal

 

[Jmac84]

Well guys I appreciate all your input. I'm going to go with retirede on this the 30 amp breaker with a 20 amp receptacle just goes against everything I've been taught. I'm going to call the manufacturer Monday and see if I can get to thr bottom of this. I was just hoping to wrap it up this weekend. Again I appreciate your time and knowledge thank you.

 

[infinity]

Well guys I appreciate all your input. I'm going to go with retirede on this the 30 amp breaker with a 20 amp receptacle just goes against everything I've been taught. I'm going to call the manufacturer Monday and see if I can get to thr bottom of this. I was just hoping to wrap it up this weekend. Again I appreciate your time and knowledge thank you.

I certainly would not use a 30 amp OCPD with a 20 amp single receptacle since it's a violation. I may opt for the #10 wire. They should just install a 30 amp plug from the factory.

 

[electrofelon]

Might consider running #6 AL SE cable for it. Stuff is cheap now, like a buck a foot, cheaper than #10 NM. Then you can use your 30 amp breaker and a 30 amp outlet.

 

[infinity]

Might consider running #6 AL SE cable for it. Stuff is cheap now, like a buck a foot, cheaper than #10 NM. Then you can use your 30 amp breaker and a 30 amp outlet.

The kiln comes with a 20 amp plug. Would you transition to copper to connect to the receptacle?

 

[Eddie702]

The controller in this kiln is fairly sophisticated. It has current and voltage sensors built in.

For all I know maybe it can be programmed to limit operation base on amps and volts.

To me the 20A plug is the decision maker. The #10 wire is a suggestion not a requirement. I didn't see a mention of a 30 amp breaker.

 

[infinity]

To me the 20A plug is the decision maker. The #10 wire is a suggestion not a requirement. I didn't see a mention of a 30 amp breaker.

The 30 amp OCPD is a non-starter as it's a violation with 20 amp receptacle.

 

[electrofelon]

The kiln comes with a 20 amp plug. Would you transition to copper to connect to the receptacle?

Okay, good point I forgot about the factory installed cord cap. I would probably seriously consider cutting it off and putting a 30 amp on. The idea of running a 20 amp plug and receptacle at 100% for long periods doesn't get me very excited

 

[infinity]

Okay, good point I forgot about the factory installed cord cap. I would probably seriously consider cutting it off and putting a 30 amp on. The idea of running a 20 amp plug and receptacle at 100% for long periods doesn't get me very excited

I agree, if it were for the warranty issue of wacking off the 20 amp plug I would just go 30 amps end to end.

 

[Eddie702]

@electrofelon
I agree
But i's the MFG decision. Not ours.

Maybe there is something in the controls programming that can limit input that we don't know about.

 

[ramsy]

This kiln might not be, but many older ones run the elements continuously until the target heat (cone) is reached, and that can be 12+ hours.

Instruction manual Pg.19 shows fastest setting for ~2000 Deg. cone is 4 hours.

KilnMaster Manuals - Kilns | Ceramic Pottery Kiln, Glass Kiln, Pottery Wheels | Skutt

KilnMaster Manuals - Kilns | Ceramic Pottery Kiln, Glass Kiln, Pottery Wheels | Skutt

skutt.com

Appendix 5 shows the only 115v model is KM614 with the * wire-size note, at bottom of table:

* .."Electrical specifications listed above are suggested guidelines. Local electrical codes may vary."

Where the NEC is adopted, and an appliance cord is provided with NEMA 5-20P plug, listed & tested to handle the continuous 2300 Watts for 4+ hour cone ramps, I believe a similarly listed 5-20R receptacle is preferred with NEC branch sized with #10cu on a 30A fuse.

Cutting off the 5-20P could find 90°C appliance conductors that burn up 75°C terminals of after market 30 Amp cord cap plug.

 

[don_resqcapt19]

... I believe a similarly listed 5-20R receptacle is preferred with NEC branch sized with #10cu on a 30A fuse.

....

Not permitted by the NEC.

 

[ramsy]

Not permitted by the NEC.

I believe you are correct, per NEC Table 210.21(B)(3)

Here is their listing page

Safety Listings - Kilns | Ceramic Pottery Kiln, Glass Kiln, Pottery Wheels | Skutt

Safety Listings - Kilns | Ceramic Pottery Kiln, Glass Kiln, Pottery Wheels | Skutt

skutt.com

On closer examination of the models registered under their UL file number, the 115v model 614 is not listed, and may be prohibited by NEC.

Search for e29997 on Product iQ | UL Solutions

productiq.ulprospector.com

That NEMA 5-20P on Pg.45-46 of the manual for the KM614, may have failed an NRTL attempt.

 

[ramsy]

Not permitted by the NEC.

You are also correct, per NEC 210.21(B)(1)