Kiln wiring...

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1793

1793

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Location
Louisville, Kentucky
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Inspector
I've been asked to install a receptacle for a Kiln. I've seen the nameplate and it is calling for 240V 24A. There is a 3wire cord attached to this unit. Its going into a commercial building space and I have a 3 phase 30A fused disconnect in the right place for the kiln.

I hope to get by to take a closer look at the kiln tomorrow, but I would like to know if a typical kiln of this size uses a neutral or is it straight 204V w/ground.

Anything special I should be looking for?

Thanks
 
1793 said:
I've been asked to install a receptacle for a Kiln. I've seen the nameplate and it is calling for 240V 24A. There is a 3wire cord attached to this unit. Its going into a commercial building space and I have a 3 phase 30A fused disconnect in the right place for the kiln.

I hope to get by to take a closer look at the kiln tomorrow, but I would like to know if a typical kiln of this size uses a neutral or is it straight 204V w/ground.

Anything special I should be looking for?

Thanks
Click to expand...

Usually, they are just straight 240 volt.

The exception may be if the kiln has electronic controls. If it just has a kiln-sitter and some manual temp controls, it's likely a neutral isn't needed.
 
1793 said:
I've been asked to install a receptacle for a Kiln. I've seen the nameplate and it is calling for 240V 24A. There is a 3wire cord attached to this unit. Its going into a commercial building space and I have a 3 phase 30A fused disconnect in the right place for the kiln.

I hope to get by to take a closer look at the kiln tomorrow, but I would like to know if a typical kiln of this size uses a neutral or is it straight 204V w/ground.

Anything special I should be looking for?

Thanks
Click to expand...

Wouldnt that pretty much eliminate a neutral? Unless it's 240V one leg, neutral, ground.
 
Usually, they are just straight 240 volt.

The exception may be if the kiln has electronic controls. If it just has a kiln-sitter and some manual temp controls, it's likely a neutral isn't needed.


What is a "kiln-sitter"?:?
 
Does the "kiln sitter" work through a contactor to operate (open and/or close) the power for the heating elements?

I am trying to assist a guy that bought a used kiln. He has purchased a digital controller to power the elements on and off instead of the "kiln sitter" that came with the unit.
 
JDB3 said:
Does the "kiln sitter" work through a contactor to operate (open and/or close) the power for the heating elements?

I am trying to assist a guy that bought a used kiln. He has purchased a digital controller to power the elements on and off instead of the "kiln sitter" that came with the unit.
Click to expand...

The kiln-sitters have the contacts inside them.

Here is a view from the back

KlnStr_Replacing_Tube_W6.jpg


The controller he bought, a PIC controller I assume, will probably not be rated for full current and will need to control a set of contactors.

Does the guy putting the controller on the kiln know what he is doing? If not, I strongly suggest using the kiln-sitter that came with the unit.

Edit to add:

Note the 105+degree 'glass' wiring in the kiln sitter, above. And the high temp materials used in the devices. That's there for a reason. Is that going to be compensated for some how when the digital controller is used?
 
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1793 said:
I made it by the job site yesterday and there is a Kiln-Sitter LT-3K. It's markings are 240V 50A. There is a 50A 3wire cord on the unit.

It is always better to see the piece of equipment and not rely on someone telling you what they have.

Thanks to all.
Click to expand...

Last question:

I have a 3 phase 60A General Duty Switch 240V fed by a 3 wire Delta Corner Grounded Service, I think. If I can get the 50A fuses should this kiln work with this set-up?
 
1793 said:
Last question:

I have a 3 phase 60A General Duty Switch 240V fed by a 3 wire Delta Corner Grounded Service, I think. If I can get the 50A fuses should this kiln work with this set-up?
Click to expand...
That will work but you have to get a dummy fuse to put in the holder that has the grounded conductor. They cost more than they should for what they are.
 
1793 said:
Thanks. Why would I need a dummy fuse if I'm only using two of the three.
Click to expand...

If you are using the grounded conductor you can not put a fuse in it. A common trip breaker is fine because it will open ungrounded conductors simultaneously, you just can't put fuses in grounded conductors as a general rule.
 
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