Transformer downstream from gen.

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yrdbrd1

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Is there anything out there prohibiting a transformer (feeding critical care panels) being fed by a generator for emergency power? Inspector has a problem concerning the fact that if the transformer goes out, no power to critical care equipment.

[ March 01, 2005, 10:03 PM: Message edited by: yrdbrd1 ]
 
Re: Transformer downstream from gen.

yrdbrd1,
Doesn't the normal power feed this same transformer? Is the gen. at maximum capacity. Is the transf. at max? If "no" to both I don't see how else you can do it.
frank
 
Re: Transformer downstream from gen.

Inspector has a problem concerning the fact that if the transformer goes out, no power to critical care equipment.
Click to expand...
So it's OK if the generator goes out?
What exactly does he want??
 
Re: Transformer downstream from gen.

The question is a generator feeding a transformer feeding critical loads. Is there more equipent involved here? Like a transfer switch? MAybe it is a set up like this;
Gen set feeder to transfer switch. Normal feeder to same transfer switch. Load side of transfer switch to transformer to critical loads. If this is the case every hospital I know does this. Inspector is goofy.
If it is how you described the where is the second source of power that is required.
 
Re: Transformer downstream from gen.

He can have all the problems in the world with it, but it's not violating any codes.
 
Re: Transformer downstream from gen.

I would be more concerned with the generator not starting.
 
Re: Transformer downstream from gen.

There was a similar question asked a while back.

Does this inspector have a grip on failure rates of Dry Type transformers?

What is his suggestion, a standby transformer with throw over capabilities? ;)

Roger
 
Re: Transformer downstream from gen.

We have ran into these types of situations before. It comes up a lot on remodeling jobs. I think the safest solution would be to have a 208v/120v generator for critical loads. But it is usually more convienent to have higher voltage generators and step down.

That leaves two options:

1. Use a single transformer on the load side of the transfer switch.

2. Use 2 transformers on the line sides of the transfer switch. Now you have one transformer just sitting there cold. I have not been able to find out what effect this would have on the transformer. Is it possible moisture will condense on it? Is it more likely to fail due to thermal shock? Is it more likely to trip a breaker starting cold?

So we have always tried to avoid #2.

I would ask the inspector "What are the odds that the transformer will fail during a power outtage?" Rattus is right: it is more likely the generator won't start.

If the transformer fails while the utility is still up, thats OK, because normal power outlets are also required in critical care areas.

Steve
 
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