Switching the neutral on kitchen equipment

[brother]

Is there a UL requirement that forbids the switching of only the neutral (grounded conductor) on a 120v warming kitchen cabinet heating element??



I know in NEC 2008 404.2 (B) forbids it in most situations, and I thought the NEC forbid it in heating elements for other appliances, but could not find it.


I can see this as a safety issue in cooking units.

 

[Little Bill]

Is there a UL requirement that forbids the switching of only the neutral (grounded conductor) on a 120v warming kitchen cabinet heating element??



I know in NEC 2008 404.2 (B) forbids it in most situations, and I thought the NEC forbid it in heating elements for other appliances, but could not find it.


I can see this as a safety issue in cooking units.

The NEC would require all ungrounded conductors be switched along with the neutral should you decide to switch the neutral.

 

[brother]

The NEC would require all ungrounded conductors be switched along with the neutral should you decide to switch the neutral.

But this is 'inside' the kitchen equipment. It appears the NEC did not cover the manufacturers equipment in this area, unless Im missing something in the NEC.

 

[GoldDigger]

But this is 'inside' the kitchen equipment. It appears the NEC did not cover the manufacturers equipment in this area, unless Im missing something in the NEC.

This does not make it an NEC issue, but if a fault to ground occurred on the low side of the heating element, the result will be that the switch will be bypasses, the hearing element will operate normally, overcurrent protection will not be triggered, and 100% of the load current will be flowing through the EGC.
If the warming element requires thermostatic control, and that control is also on the neutral, that control will also be lost.
All good reasons not to design the equipment that way, and also not likely to get UL approval.
I wonder if the portable cord or hardwired supply to the unit was installed incorrectly?

 

[Little Bill]

Pictures would be nice!:happyyes:

 

[kwired]

But this is 'inside' the kitchen equipment. It appears the NEC did not cover the manufacturers equipment in this area, unless Im missing something in the NEC.

NEC does not cover internal wiring for appliances, if it is an issue it would be with NRTL's and their listing requirements.

 

[brother]

Pictures would be nice!:happyyes:

I haven't got the picture trick down yet. but basically it would just be a rough drawing sketch of a heating element that has a switched neutral from the thermostat.