480/277 Service

[aftershock]

That's what is has written the big green transformer outside the back of the building.

Someone has trashed some of the electrical in this vacant building. It used to be a Central Hardware, then it became a call center for several computer related companies. There is switchgear and configurations I have never seen before.

Anyways we are going to try and get temporary power restored so we got some lights and receptacles to work with. 480/277 coming in from the transformer. POCO is gonna see about getting us a 480/v meter can, but, since there are CT's already in the transformer we may have to stick with the CT meter.

I need the code refrences for my service disconnect after the meter and before a buck trasformer that will bring it down to 208/120. Edit: and any other related code articles I may need to look at for this type of service.

I will probably have more questions later.
We are still under the 2002 cycle in my county but I have a 2008 here at home with me.

This building went through a major electrical remodle about 10 years ago. This leaves me to believe that a set of electrical prints had to have gone through the engineering dept of our local code enforcement for approval before a permit would have been released to start the work. I am trying to get my boss to see if he can obtain a copy of those prints so I may be able to understand what circuits are suppose to be in which panels.

The thieves destroyed the main switch gear as well as a few other enclosers and took as much of the heavy copper they could get away with.

This is going to be a challenge as well as a learning experiance. I just need to get the temporary power started.

Thanx in advance.

 

[iwire]

Rick you would not use a buck transformer here.

You would use a 480 volt delta - 208/120 wye transformer for this.

We have dozens of these for temp use, I am sure you do not, so.... you really should figure out at least an idea of what the future holds for this space so you buy the stuff once. 480 volt equipment is to expensive to throw away.

But if all your looking for is a little bit of power you could put in a 100 amp 480 breaker in a single breaker enclosure (service rated of course and you really need to find out the available fault current from the utility) This is not going to be a cheap breaker. From there you could go directly to a 45 to 75 kVA 480 -208Y120 transformer and that would supply a 100 or 225 amp main breaker panel.

Rick, is there anyone you know that is familiar with this that you could bring on site. I mean no offense but you sound a bit inexperienced with 480 services and they are not forgiving in the least.

If you do install a transformer you have to comply with 250.30.

 

[aftershock]

Rick you would not use a buck transformer here.
You would use a 480 volt delta - 208/120 wye transformer for this.

I may have used the wrong terminology on that one
There are still some transformers intact in this structure and I think the one you cited is the one I was looking at. I will double check.

We have dozens of these for temp use, I am sure you do not, so.... you really should figure out at least an idea of what the future holds for this space so you buy the stuff once. 480 volt equipment is to expensive to throw away.

Im gonna try to get the info off of that transformer I saw. From what I can gather, those who own the building (we do alot of work for them) just want some type of temporary power restored and that the future tennants will be responsable for any future electrical upgrades

But if all your looking for is a little bit of power you could put in a 100 amp 480 breaker in a single breaker enclosure (service rated of course and you really need to find out the available fault current from the utility) This is not going to be a cheap breaker. From there you could go directly to a 45 to 75 kVA 480 -208Y120 transformer and that would supply a 100 or 225 amp main breaker panel.

The breaker that feeds the transformer I mentioned as probably being what we need is still onsite as well. One of the things that was not taken. I will have to find an enclosure for it. Agian I will look closer at it. I told the POCO to figure me up for a 200 amp load when he asked for a load calc. We are just gonna get the lights and some receps going. It's so dark inside so I could not get pictures.

Rick, is there anyone you know that is familiar with this that you could bring on site. I mean no offense but you sound a bit inexperienced with 480 services and they are not forgiving in the least.

If you do install a transformer you have to comply with 250.30.

I know of an electrical company that my boss's son runs. In my opinion I wish he would let this bigger more experianced company take care of restoring the power and switch gear. I would like to learn this and yes, I am ver inexperianced at this He could have me do the T/S work and re-pulling panel feeds and at the same time I could learn some things I have never done before. I will see if I can talk him into this. My boss threw me in the water 6 months green and told me to swim or drown. Single phase 240 wasn't a problem to learn, but yeah, 480 can get me killed.

Thanx.

 

[augie47]

Single phase 240 wasn't a problem to learn, but yeah, 480 can get me killed.

Thanx.

NEVER FORGET. Either voltage can deliver a fatal bite, one simply has bigger teeth. Shock and arc-flash from any voltage is always something to keep in mind.

 

[aftershock]

NEVER FORGET. Either voltage can deliver a fatal bite, one simply has bigger teeth. Shock and arc-flash from any voltage is always something to keep in mind.

You are correct. I should have stated that single phase 240 was easier for me to grasp the concept of since I see/saw it's affects in everyday life. 480 being out of my scope for reasons not limited to being experianced with but also not being around it's affects on how it is used.
Im not good with words