Power On/Off Switch Required ??

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Brian9

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Mansfield, Ohio USA
Greetings --- I am an electrical engineer at an OEM tasked with retrofitting a submersible pump control panel. The new control panel needs a moisture/thermal relay wired in, however, there is no room physically for the relay in the original panel. I will need to provide a new 10x8 panel to house the relay and then have the customer run conduit between the panels. The 10x8 will be mounted close to the original panel, well within reach (power cable from the pump will go to the original panel, moisture/thermal sensing cable will go to the 10x8 panel --- both cables from the same pump, so panels will almost have to be mounted close to each other).

Really trying to keep the cost down for production of this new panel so I really don't want to have to include a 120VAC power on/off switch on the door. Is there anywhere in the NEC --- like an obscure execption or something --- that gives me an out from having to provide the on/off switch on the 10x8 panel? It is very close to the supplying panel. Could I put a label on it or something?

Thanks, Brian9
 
Does the 120v come from the main control panel or another source?
 
Control panel On-Off switches are not part of the NEC. For the most part, the NEC only cares that a disconnect means exists somewhere and that it is lockable.

You may want to look into NFPA79 for guidance on control panel disconnects and marking requirements.
 
Brian9 said:
Greetings --- I am an electrical engineer at an OEM tasked with retrofitting a submersible pump control panel. The new control panel needs a moisture/thermal relay wired in, however, there is no room physically for the relay in the original panel. I will need to provide a new 10x8 panel to house the relay and then have the customer run conduit between the panels. The 10x8 will be mounted close to the original panel, well within reach (power cable from the pump will go to the original panel, moisture/thermal sensing cable will go to the 10x8 panel --- both cables from the same pump, so panels will almost have to be mounted close to each other).

Really trying to keep the cost down for production of this new panel so I really don't want to have to include a 120VAC power on/off switch on the door. Is there anywhere in the NEC --- like an obscure execption or something --- that gives me an out from having to provide the on/off switch on the 10x8 panel? It is very close to the supplying panel. Could I put a label on it or something?

Thanks, Brian9
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If the panel that you are modifying (or supplementing) is listed, then whatever listing applies to that panel will apply to your new accessory panel.

If your shop is a listed panel shop, then the standards you are held to will apply.

The NEC is going to stop applying where your manufactured system is connected to a building's electrical distribution system.

Is this a UL 508 system?
 
Yes, this is a UL 508A system, but the label will be removed if the retrofit cannot connect to existing terminals in the original panel. The original panel has a CB disconnect, as well as a step-down transformer with primary and secondary fuses. 120VAC power to the new retrofit panel will come down stream from the transformer secondary fuse.

Since you said the NEC is vague on this level of application --- which is kind of what I was seeing --- I plan to follow UL 508A 30.3.1 exception, which leads to 60.1 and allows for a disconnecting means outside the new control panel provided it is provided somewhere else --- in this case in the original panel --- and the new panel is properly marked.

Brian9
 
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