Machine with a Tank Heater without UL approval

[UL_MTR_Stephan]

Hi guys, Here is Stephan, I'm an electrical desgin engineer from Germany and UL MTR of our company.
We are in the PanelShopProgram from UL Germany (NITW)

We are supposed to build a control cabinet for a machine according to UL/NFPA standard. Now the customer has a tank heater in the machine that does not have UL approval (permanently installed in a tank). Heater 920W 230V / 4A (We want to generate the voltage via a 480V / 230V transformer.

Are there exceptions for something like this in the NEC or NFPA79?

 

[petersonra]

UL508a only covers stuff that is in the control panel. The heater is not in the control panel so is outside the scope of UL508a.

There is no issue with providing controls and voltage for this heater from the control panel as long as you follow the rules for such controls.

 

[UL_MTR_Stephan]

Hey Petersonra,
Yes, I know, the overcurrent protection of the heater is in accordance with the specifications of 31.6 Sizing of branch circuit protection for heater loads. Everything is fine in the control cabinet. I was just concerned about using devices in the field that do not have UL approval. And whether additional measures are required.
Okay thanks

 

[don_resqcapt19]

Hey Petersonra,
Yes, I know, the overcurrent protection of the heater is in accordance with the specifications of 31.6 Sizing of branch circuit protection for heater loads. Everything is fine in the control cabinet. I was just concerned about using devices in the field that do not have UL approval. And whether additional measures are required.
Okay thanks

There is an OSHA requirement that says all electrical equipment used in a work place must be listed by one of the NRTLs (Nationally Recognized Testing Laboratories), but that is rarely enforced. UL is just one of the NRTLs that can list the equipment.

 

[Jraef]

There is an OSHA requirement that says all electrical equipment used in a work place must be listed by one of the NRTLs (Nationally Recognized Testing Laboratories), but that is rarely enforced. UL is just one of the NRTLs that can list the equipment.

Yes, that’s the issue. The NEC indirectly calls for listing of electrical devices as well, but listing the control panel does not remedy the fact that another component on the machine is not listed.

There are steps you can take under UL-508A to use unlisted components INSIDE of the panel and add them to your procedure so that you can list the panel, it involves using barriers inside and a GFCI ahead of the circuit for them. But that doesn’t help with external devices.

 

[Fred B]

Was the heater incorporated as a part of the total equipment? If so the whole equipment with it's individual components "might be" listed but not every component piece individually. If the heater was an add-on there may be an issue.
Not sure if replacement parts that are used in a listed equipment need an independent listing though. Would at least say it should be obtained from the equipment manufacturer if not independently listed.

 

[augie47]

Our inspectors supposedly will look for a NRTL on the entire assembly.
That said, if the control, panel has a sticker the job often passes