480 put to a 208 system

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texie

Senior Member
Location
Fort Collins, Colorado
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Electrician, Contractor, Inspector
Just got a call from a friend I worked with for years in Florida. He got call to a large condo where the POCO replaced the pad mount xformer due to leaking oil. Problem is that it was a 208 system and they installed a 480 replacement transformer and energized it before realizing what they had done. Did a lot of damage. Magic smoke came out all over the building. Kind of like getting the wrong limb operated on because nobody bother to verify the details. Gonna be an expensive claim.
 
Oooooops, regardless we are the POCO so it's not our problem. 😄

Roger
 
texie said:
Just got a call from a friend I worked with for years in Florida. He got call to a large condo where the POCO replaced the pad mount xformer due to leaking oil. Problem is that it was a 208 system and they installed a 480 replacement transformer and energized it before realizing what they had done. Did a lot of damage. Magic smoke came out all over the building. Kind of like getting the wrong limb operated on because nobody bother to verify the details. Gonna be an expensive claim.
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Working in this industry as long as I have it still boggles the mind why nameplates aren’t checked against what’s coming out..
I always thought that was rule #1.
I had a job where Duke had to change out a pad mount, I was the “sub for the sub” to connect a temporary generator for him...
Pike set a 480 PMT on a 208 service. They got EXTREMELY lucky as this was a bank (Money bank). They got a call the next day that the generator hasn’t stopped running since they installed the pad mount..
Put the right PMT in and all was well.
 
Used to do a lot of HVAC roof top units. You wouldn't believe all the times that replacement roof top units get set and no one realizes there the wrong voltage until the crane is gone
 
In my decades as an electrician I can say that I have seen some pretty colossal mistakes that have done a lot of damage like this. Some even with injuries as a result. Almost invariably it was something obvious that should have been caught long before it was to late.
 
Somebody was telling me about a generator install on a 911 call center, building was 208Y/120V, gen was 480Y/277V, magic smoke was let out, would not want to be in either the engineers, or foreman's shoes on that one. Colossal screw up there and lots of opportunities to avoid the problem prior to startup just by reading the data plate.
 
Many utilities place large stick-on labels on the outside to designate the transformer voltage and KVA rating. Makes it easier for line crews to find the correct units. It's usually left up to the warehouse guys to do the labeling. Not all are careful enough to check the nameplate against the shipping paperwork. Line crews are usually going by the work-order info. Mistakes happen...
 
Sometimes the labels are wrong. I had one where the PoCo was supposed to install a 750kVA pad mount transformer for a pump station with big pumps, and the one they installed was dinky, about 2ft high, 3 ft. square. I complained, they sent out a technician, who opened the door and showed me the label that said 750kVA. I told him the label was obviously wrong, because what I was looking at was NOT a 750kVA transformer. Long story short, after several back and forth arguments, it turned out to be 75kVA. But they kept reading that stupid label and insisting I was wrong. Luckily on mine the only thing that was lost was a lot of time.
 
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