Weird Electrical Service (What am I working with?)

[mrb]

The nipple on the end of the conduit and the tape around the wires may be throwing what I think I see off. It looks like 3 pieces of #4. What bothers me is the ground lug being mounted on the nipple. It also appears this is only a frame ground as I see what looks like both ends of the ground line (one cut off near the knockout.) Looks a lot like #12 ! Love the shredded wire strands laying about the bottom of the box! You need to call someone in big time.

the ground lug on the conduit coming in is a bonding bushing which appears to be installed correctly. I cant however tell what the lug on the end of the EGC (frame ground as you call it) is attached to. Is it just sitting there?

The EGC appears to be a #10 which would be the proper size for a circuit up to 60 amps. (Unless its a 60 amp circuit using #4 conductors due to voltage drop, then you would have to bump the EGC up a size)

This post is theory only and not instructional in nature and not electrical or code advice. Consult a licensed professional.

 

[mrb]

Looking at the picture, which clearly shows 3 fuses, if these are selected for the correct rating based on the wire being used in the feed FROM this unit then why would you need additional protection? I would have thought that the purpose of this box and fuses was to provide this protection


Sharyn

you wouldnt need additonal OCP based on the scenario you outlined. If for example you were tying #2 tails into a 400A company switch, you would need OCP to protect those #2 tails within the distance allowed under the NEC Tap Rules.

 

[journeymanjohn]

Looking at the picture, which clearly shows 3 fuses, if these are selected for the correct rating based on the wire being used in the feed FROM this unit then why would you need additional protection? I would have thought that the purpose of this box and fuses was to provide this protection


Sharyn

How can they be based on the wire fed FROM this disconnect?? There are no wires being fed FROM the disconnect..........(yet).

 

[SHARYNF]

the user would select the correct fuse rating for the fuse based on what wire was selected to connect the down stream load to. Remember fuses are to protect the wiring between power source and load. At this point with nothing connected on the load side the fuses are not doing anything. These were evidently used in this disconnect to protect some sort of 3 phase motor. SO when the wiring and the load is determined and installed, then the fuses can be selected for the proper rating.
The whole purpose of fuses in a fused disconnect is to protect the wiring between the disconnect and the load

Sharyn

 

[NickVon]

That looks very simliar to the Electric Distro Box for my Theatres LMI Dimmer Rack

 

[BenTev28]

Hey all -

Thanks for the advice and comments. The electrical service in this theater is definitely wonky at best. I'm guessing that the copper strands left over are from someone who just decided to trim down 4-0 instead of using 2-0 (which is what the lugs are sized for).

For right now we're running an Iso transformer from the panel, thereby creating the neutral. From there we're going to the distro for the sound system. The long term plan _is_ to have an electrician in to run a neutral into the box (with larger conduit if needed). I did install strain relief before tying in. Fuses are also now rated correctly for wire gauges and load.

I definitely appreciate the safety advice.... that's part of the reason I ask these questions here instead of elsewhere. For anyone else running into this though, the Iso transformer is a (relatively) affordable solution for limited runs.

 

[derekleffew]

... For right now we're running an Iso transformer from the panel, thereby creating the neutral. From there we're going to the distro for the sound system. The long term plan _is_ to have an electrician in to run a neutral into the box (with larger conduit if needed). ...

While I said above "...pulling a neutral is really the best course of action," I meant to allow for greatest flexibility for general purpose use. For audio, I wouldn't eliminate the isolation transformer if budget allows, whether or not there's a primary-side neutral.

 

[mrb]

Hey all -

Thanks for the advice and comments. The electrical service in this theater is definitely wonky at best. I'm guessing that the copper strands left over are from someone who just decided to trim down 4-0 instead of using 2-0 (which is what the lugs are sized for).

For right now we're running an Iso transformer from the panel, thereby creating the neutral. From there we're going to the distro for the sound system. The long term plan _is_ to have an electrician in to run a neutral into the box (with larger conduit if needed). I did install strain relief before tying in. Fuses are also now rated correctly for wire gauges and load.

I definitely appreciate the safety advice.... that's part of the reason I ask these questions here instead of elsewhere. For anyone else running into this though, the Iso transformer is a (relatively) affordable solution for limited runs.

how is the required GEC for the transformer handled?