Transformers

Status
Not open for further replies.
D

DENN M.

Member
Just looking for some input.......typically as a standard practice, I don't feed more than 1 panel directly from the secondary side of a transformer. I have a customer whose engineer is trying to convince him to oversize the transformer so that he can add another panel to the secondary side of transformer later. I don't like the idea. Anybody have advice or code sections to support either position?

Sent from my SM-N910V using Tapatalk
 
Code compliant if installed correctly. If he wants to write a big enough check you can install a transformer for any number of panels.
 
DENN M. said:
I have a customer whose engineer is trying to convince him to oversize the transformer so that he can add another panel to the secondary side of transformer later. I don't like the idea.
Click to expand...

This is common, what don't you like about the idea?

Consider the entire building is being supplied from one transformer, heck that transformer may supply more than one building.
 
augie47 said:
Code compliant if installed correctly. If he wants to write a big enough check you can install a transformer for any number of panels.
Click to expand...

To add some "color", keep in mind Note 2 for Table 450.3(B) which says that the additive total of secondary breaker ratings can't be more than what it would have been if there was one breaker.
 
iwire said:
This is common, what don't you like about the idea?

Consider the entire building is being supplied from one transformer, heck that transformer may supply more than one building.
Click to expand...
Well, I'll elaborate first.......The engineer is requiring a 225kva transformer for "future use", but the only thing on the secondary side of that transformer will be a single phase 400amp panel. A lot of overkill for something that may never change. Also, in an industrial setting, I don't like to have more than 1 panel on the secondary side because if there's any issue with the transformer or if you have to shut it off for any reason, there is more equipment affected and more production lost.

Sent from my SM-N910V using Tapatalk
 
ron said:
To add some "color", keep in mind Note 2 for Table 450.3(B) which says that the additive total of secondary breaker ratings can't be more than what it would have been if there was one breaker.
Click to expand...
I hear ya......Thanks

Sent from my SM-N910V using Tapatalk
 
DENN M. said:
Well, I'll elaborate first.......The engineer is requiring a 225kva transformer for "future use", but the only thing on the secondary side of that transformer will be a single phase 400amp panel. A lot of overkill for something that may never change. Also, in an industrial setting, I don't like to have more than 1 panel on the secondary side because if there's any issue with the transformer or if you have to shut it off for any reason, there is more equipment affected and more production lost.

Sent from my SM-N910V using Tapatalk
Click to expand...

maybe he knows about some future plans that are not considered any of your business at present.
 
ron said:
To add some "color", keep in mind Note 2 for Table 450.3(B) which says that the additive total of secondary breaker ratings can't be more than what it would have been if there was one breaker.
Click to expand...

But, to keep the "color" wheel active, Note 2 only applies when one is depending on secondary overcurrent devices for transformer protection.
If I protect my primary per 450.3(B) then I could have any number of secondary panels of any rating provided I met all the Art 240 rules.
 
Status
Not open for further replies.
Top