UL 508A and UPS

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Alan Davison

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Vancouver, WA
Can anybody point me to where it says you can OR cannot put a UPS into a 508A control panel?
We have done several with a UPS in the past and now suddenly our field rep has a problem with it. He said they started looking at them last year and not allowing them. There is nothing in writting (his words)!!
I really need some help here, we are going to ship this cabinet without the UPS installed to clear the variance. The customer does not like this answer and I would at least like to show them in writing where it says we can't install the UPS.

Thanks

Alan
 
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jim dungar

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Wisconsin
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PE (Retired) - Power Systems
Alan Davison said:
Can anybody point me to where it says you can OR cannot put a UPS into a 508A control panel?
We have done several with a UPS in the past and now suddenly our field rep has a problem with it. He said they started looking at them last year and not allowing them. There is nothing in writting (his words)!!
I really need some help here, we are going to ship this cabinet without the UPS installed to clear the variance. The customer does not like this answer and I would at least like to show them in writing where it says we can't install the UPS.

Thanks

Alan
Click to expand...

If by "field rep" you mean your UL inspector, then it is up to you to show him where it is allowed by 508A. UL508A is their standard therefore they get to make up the rules. The NEC does not address what can or can not be inside of control panels. NFPA 79 does address control panels but not these types of specifics.

How were you connecting your loads to the UPS? Was the UPs after a GFCI protected outlet in your panel?
 
tom baker

tom baker

First Chief Moderator & NEC Expert
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Bremerton, Washington
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Master Electrician
I have been using a 550VA Allen Bradley 1609 UPS mfg by APC that is designed to be din rail mounted. It has wiring terminals, as opposed to receptacles/male cord. Its more expensive than a comperable UPS but worth the extra. I also like it as it has dry contacts for alarms and can have an ethernet module installed.
 
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benaround

Senior Member
Location
Arizona
Alan,

Nec 2005, Article 409, Industrial Control Panels , was new to the 2005 code

book. Most of the issues I've heard about stem from SCCR's of components.
 
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james_mcquade

Senior Member
it might depend on your application.
if the ups is being used to power a plc during a power failure, then you must
be extremely careful. for example, a siemens plc will burn up when connected to a ups after a couple of weeks (based on information from an associate who had to replace several units).
regards,
james
 
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