contactors / relays inside breaker enclosures

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ultramegabob

Senior Member
Location
Indiana
every once in a while I run across contactors or relays installed inside breaker enclosures, usually to serve parking lot lights. Is this legal? if not what code reference?
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
ITE made a lot of these from the factory, I still see a few new ones, but don't remember who makes them. Of course these are UL listed, the ones you are talking about are probally field installed?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Bob, we do a bit of commercial-kitchen fire-suppression wiring, often system upgrades, where we have to figure out how the present system is wired, and re-wire so it conforms to newer rules.

More than once I've seen a contactor for appliances inside the panel. On one job, we had to wire another appliance to the system, so I mounted a 2p 20a contactor under the existing one.

I guess it's as easy a place as any to intercept the circuit, and since the wiring for the relay coil was already there, why not add the new one in the same place, so that's what we did.

Added: Legal? Maybe, maybe not; I haven't checked. It sure was the best place to add the new one, since the old one was already there.
 
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Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
I think the answer lies in where you are. If you are in a state that requires NRTL listing (such as UL), then unless the enclosed breaker was listed with that specific contactor or relay in it, the labeling was violated and technically could not be acceptable to an inspector. If not, you are on your own and it is up to you to determine suitability.

From an engineering standpoint, breaker enclosures are sized based on wire bending space and air volume for the expected heat rise. If you add devices, you could be in trouble on either issue. If the new device is mounted in such a way as to not allow enough wire bending space, it could violate code with or without NRTL listing. If the devices added produce heat, you could be in trouble for the current rating of the breaker.

That said, it's also true that breaker manufacturers don't make a different size box for every trip rating of a breaker; usually just one per frame size. So for instance if you have a 40A breaker, the box is probably the same for everything up to 100A. In that case you may be able to accurately judge the wire bending space issue on your own if, as in the above example, the space originally provided in the box design was for much bigger wire than what you are using. But adding a lighting contactor may or may not negatively affect the breaker current rating and chances are you will not have enough information available to you, such as how much extra heat you can add in to the enclosure before de-rating becomes necessary.
 

rodney_phillips

New member
contactors / relays inside breaker enclosures

Inside the new enclosure of the Orange system, at least one of the following devices of the Modulo series can be fitted in addition to a starter, composed by contactor and thermal overload: voltage relay PMV10 A440, frequency relay PMF20?, level control relay LVM20-25-30? or sequence change relay LVMP05. A switch disconnector, type 7GS?A, also can be fitted.
A variety of push buttons, selectors and/or pilot lights can be mounted on the cover.

_______________
rodney
Minnesota Alcohol Addiction Treatment
 
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