ohynottony2
join:2007-11-17
Canada
| noob question about wire/fuse size on a transformer
Hello , I am new here and a noob when it comes to transformers, I could really use some advice from a electrician.
I'm not familiar with large transformers, I mostly do electric motor control, for motors under 10 hp , pump protection etc.
This is a greenhouse company, the owner is cheap and refuses to sub this work out to an electrician. ( which I am not , but but have 3 year electrical technologist diploma from many many moons ago )
They ask me to install a combination panel as well as a 50 kva single phase, 600v/240v transformer to supply it, this is to replace a 17kva of the same. ( because they cooked the 17 )
Basically I need to know what size fuses do I need on the 600v disconnect to the transformer, and what wire size from the secondary side to the 100 amp combination panel do I need.
Just doing very very basic calculations from my old college text books, which i haven't opened in many years, I figured 80 amp fuses would be safe on the primary, and that the secondary is capable of 210 amps?
Is this correct?
Since the new combination panel has a 100 amp main will #3 /600v, copper wire be ok to supply the comb. panel, as well at the primary on the transformer?
Another question if I can.... if they every decided that a 100 amp combination panel was not large enough to meet their needs , and wanted to go with a 200 amp combination panel, would #2 aluminum be safe to supply the panel?
thanks from you time
Tony
just a note, there was no combination panel with the 17 kva transformer, just a load centre ( no main or fused disconnect ), also they had 40 amp fuses on the primary... hence the cooked transformer.
I cannot refuse to do this , I will just get laid off and not be called back, and someone with even less knowledge than me will end up doing it, I just want to keep it safe, and keep my job. |
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dgilbert
Good Bye My Friend
Premium,MVM
join:2002-06-15
none
clubs:
| this is NOT somethign that should DIY. this is one of those situations where you stand your ground and say a pro MUST be brought in. i know you say you cannot refuse, but you should.
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Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine! |
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yock
TFTC
Premium
join:2000-11-21
Fairfield, OH | reply to ohynottony2
You really gotta think about where not refusing gets you here. If your work causes an electrical fire, you could pretty much end up losing everything you own.
Know your limits, and stand your ground. |
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ohynottony2
join:2007-11-17
Canada
| said by yock  :You really gotta think about where not refusing gets you here. If your work causes an electrical fire, you could pretty much end up losing everything you own. Know your limits, and stand your ground. The thing is no work at this place has ever had a licensed electrician performing the work, expect for the back up generators, and the main hydro.. because the owner didn't have a choice ....If you could just answer my questions it would help a lot
I recently became completely deaf, both ears ... I don't lip read well at all . I haven't been successful finding another job ... period.
I'm good at what I do, and proper safety practices, I'm just not very familiar with large transformers.There are many things here that were done ( not by me )just plain wrong, and I am trying to correct them.
Though I value your advice, and realize that's what I should do...if I don't do it, Ill get laid off and not called back... how then an I suppose to support my family?
If I don't do it ,someone else with much less knowledge about electrical work will do it... and Ill be out of a job
so please just answer my questions if you can |
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Dennis
Premium,Mod
join:2001-01-26
Algonquin, IL | reply to ohynottony2
I'm sorry, but this is really beyond a DIY forum and is very very dangerous. |
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