We have all seen those stainless steel (SS) electrical enclosures by traffic lights and outdoor lighting. Usually there is at least 1 or more pipes feeding into them. Now inside the pipe you have a 200 amp feeder enter and leave the SS enclosure, tap off a 60-100 amp line, go to a small 4-6 circuit panel.
Some questions,
1) Do you need a main on the small circuit panel?
2) Can you have open splice/tap or does that have to be enclosed in a box/through?
3) When the wires leave the feeder conduit, can they just run freely or be sleeved into a through where the tap will be made?
I hope I made myself clear, I have a friend ask me these questions.
Harold:
All that I have seen doing inspections are:
2" RGC w/service into PS meter pan
Nipple to 60/100 amp CB panel with 60/100 amp main CB
1-20 amp for the token 20 amp, 120 volt GFI receptacle.
and via 1" RGC from this enclosure to the controller.
1-20/30 amp, 2 pole that feeds controller cabinet.
To my understanding, my responsibility stops at the feeder to the control cabinet.
The above is for Township traffic signals only, not DOT.
We have that type of enclosure for various Twp needs, all have PS meters, a few have 2 circuit panels w/o mains for 120 volt receptacles.
Harold:
I neglected to include...
Grounding/bonding bushings on all conduits, 1 rod are 'standard' spec & installed.
I have an enclosure similar to a traffic light box that is used for a pedestrian crossing system. That was one royal mess of control wiring. I have to look if I still have the pics. The service (meter & panel) was inspected and passed; I went back for a 'Final' & that's when the mess turned up. It took two shots to make it compliant. They installed Panduit to secure/support/contain the LV-control.
John,
I have seen that type of install before. This one is a large tree farm. The main building is about a mile in from the street (Or it seems like a long distance). The POCO is bringing in HV cable to a transformer. Then from the main building back to the street, they are bringing a 200 amp feeder to 3-4 SS enclosures for pole lighting, auto gates, 120 recpt. etc. So the EC wants to run his feeder back down the road, go in and out of SS enclosures. Then in each SS box, tap the feeder, and go to a 6-12 circuit sub panel. Which will provide for misc. equipment.
My thought to him at the SS box was to enclose tap inside a small through, then nipple up to sub panel. This way, no open splices and there would be a main on sub panel to protect the tap.
His reply was that inside a SS box, open conductors would be allowed. He said that the whole enclosure would be rated for splices and open conductors. I can agree with him, but I think it would be safer my way. I know that "My way" does not mean the right way and as long as it passes the NEC it should be allowed.
Harold:
I would ask the EC for the mfg cut sheet/spec for the enclosure as a CYA.
Personally, I don't see any issue with what is proposed. Your way, IMHO is a more professional way. Consider also, the interior space within the enclosure relating to a wireway, etc.
John,
I think the cut sheet would just say it is listed as an enclosure. My thought of using the through inside the enclosure is that there is less chance of anyone going back in there and messing with the tap. It will also protect the tap wires since they too would be enclosed.