If this it the same gate as your thread about wire size, you should have spare capacity on the 30A circuit that is run out there. Could you tap a transformer off of that?

 

So there is an existing single phase transformer installed.

Its current wired 480 to 240v. Its only .5 kva and already has a heater for the hydraulic tank and a heater for the hydraulic cylinder on it. I dont know what those heaters pull but im guessing the transformer is about maxed out.

I need like 5 amps at 120v for the new heater pad. I thought about upsizing the transformer. Not sure if thats easier or not.

That brings up a question though. I dont do a lot of transformers. Could I technically connect a neutral to the x3/x4 to create a center tapped 120/240v off this transformer?

 

So many jobs I've been on ran troughs above the panels for this and many more reasons. It should be standard.
Anyone who uses LBs in that situation should be shot, hope it wasn't you.

Just nipple between the panels, unless there's a code reason not to. It's a 20min solution.

 

Why can't you just run a conduit out of the 208V panel to the control cabinet, then share the conduit to the gate (assuming that phallic symbol is circling the 2 conduits out of the control cabinet)? If you circled the 2 conduits with condulets from the 480 panel with that red eggplant, just cut out the condulets and install a 6 or 8" box. Easy peasy. Done in 2 hrs, charge 8.

 

Yes the two conduits out of the 480 panel with the conduit bodies are the ones in question. Particularly the far left one. I has thought about just putting a small pull box in place of the conduit bodies.

 

Hopefully they have that xformer grounded in some way and not floating. I would probably check the current with a tong meter and if the capacity was there, I’d create a neutral with X2 and x3 and grab my 120 from there.

 

Well the case is bonded. But as far as I can tell there is no connection from the secondary side to ground.

Like I say its only .5 kva and has two 240v heaters on it already. I need 4.7 amps for the new heater pad. Which if my math is right already exceeds .5 kva.

 

Do they make a 480v heater?

 

First thing to do would be to find the wattage and voltage requirements of your existing loads, then what size 480 branch circuit conductors and breaker is feeding the transformer. Add in the wattage of your new loads.

Do the calculation on the total requirements for creating a three wire secondary 240/120. then upgrade the transformer and 480 branch circuit if required, then you could provide a small 3R loadcenter to split up the capacity between your loads, and leave the interior piping as existing. If you do it right, you could provide a bit of spare capacity for your other unplanned loads out there.

 

I agree and had the same idea. It solves the problem and avoids running 120V with 480V. It is often done and does not violate any NEC codes (I don't think) but can be a PITA for troubleshooting and isolation.

 

Guess I could pipe between the two panels and just

312.8(A) will probably allow feed through. It looks very easy. Make sure it's under nipple length.

 

I think I'd upgrade the transformer. If there are #12's feeding the existing one you should be able to pull 16 amps at 480V if they're attached to a 20 amp breaker. That should land you at a 7.6Kw on the primary side. You wouldn't have to change any breakers or replace any wiring. It looks like the transformer is only using 2 legs of the 3 phase circuit. There may be a spare leg in the box up there.

 

Yes the existing transformer is single phase off two legs of the 480v. Currently its downstream of a 10 amp breaker in the control enclosure and a set of 4 amp fuses.

 

A shared alternating heater circuit refers to using one electrical circuit to power multiple heaters,

 

...

 

So we need to add a winter kit to our automatic gate at the plant so I need to come up with 120v power out at the gate. It already has a 480v feed running to it. Running an additional pipe is very much non ideal.

Originally I thought maybe I could tie into the existing transformer, but that doesn't look feasible. Its only a .5kva transformer and already has a hydraulic tank heater and a cylinder heater on it.

This leaves me trying to run an additional 120v circuit from the building in the same pipe as the 480v circuit.

The pipe appears to be all 1 inch so I should have plenty of room. However I need some ideas on how to most easily accomplish the conduit joining.
View attachment 208651

The circled pipe is the one I need to get into. The new 120v circuit would come out of the panel on the left.

Guess I could pipe between the two panels and just pull through the 480v panel. I think thats allowed, isnt it? My only other thought is to take the conduit body off, mount a small junction box and pipe over to the other panel.

Anybody got any better ideas?

i agree with CMP

two different voltages to ground is NOT allowable in the same pipe
277 VS 120

 

By what rule? I questioned if it was allowed but I dont think its actually a violation.

 

So we need to add a winter kit to our automatic gate at the plant so I need to come up with 120v power out at the gate. It already has a 480v feed running to it. Running an additional pipe is very much non ideal.

Originally I thought maybe I could tie into the existing transformer, but that doesn't look feasible. Its only a .5kva transformer and already has a hydraulic tank heater and a cylinder heater on it.

This leaves me trying to run an additional 120v circuit from the building in the same pipe as the 480v circuit. The pipe appears to be all 1 inch so I should have plenty of room. However I need some ideas on how to most easily accomplish the conduit joining.
View attachment 208651

The circled pipe is the one I need to get into. The new 120v circuit would come out of the panel on the left.

Guess I could pipe between the two panels and just pull through the 480v panel. I think thats allowed, isnt it? My only other thought is to take the conduit body off, mount a small junction box and pipe over to the other panel.

Anybody got any better ideas?

Small xfmr off the 480 circ? Mind you I dont know all the particulars out in the field.

 

Where is this delineated in NEC? Insulation is what regulates conductors in conduit.

 

 

OK Google. Instead of pasting doc talking about NEC, why not post the real articles?

 

Already has tank heat and a cylinder heater and it needs more heat?

I'd go bigger transformer before messing with an underground conduit of unknown condition. How big is the motor on the hydraulic power unit?