Access to back of transformer?

[eletrick]

Heres what I got,
A 500KVA transformer in a room with other electrical equipment
Main switch with distribution on one side of the transformer 120/208 vac distribution on the other. And there is 6? of space from the transformer. Equipment is set against a furred out CMU wall on a housekeeping pad, nothing in the equipment requires access to the back (so far I think this is a standard set-up). The transformer is 12? off the wall
The 480 vac connections are in the front of the transformer again typical now the possible problem: the load side connection are in the back,
My question-110.26 and 110.26(1) (a) where is states rear access is required??.30??
And yes if the transformer is bumped out 17? other problems will raise there ugly head such as obstructions and adding doors moving the other equipment to have access to the rear of the transformer ECT?
This is the first time I have seen a transformer with this set up in-doors I have seen this on a roof but there was not access problems with that.
Clear as mud??????

 

[raider1]

Is the only access to the load side connection through the back?

If so then sufficient access and working space should be provided.

Chris

 

[buddhakii]

What if you could access them from the top?

 

[Duke E]

I would apply condition 2-3?6? to the back of the transformer if access is required. I?m amazed that it was connected at all given it only has 12? clearance.

 

[eletrick]

the load side maybe....you would have to reach over the coils.Would not be easy or pretty and I`m not sure where the "XO" bus is at??

 

[infinity]

If all of the connections are accessible from the front then the back should only require enough space for ventilation. That information should be on the transformer.

 

[eletrick]

I`m going to go and take some photos..maybe that will help

 

[buddhakii]

the load side maybe....you would have to reach over the coils.Would not be easy or pretty and I`m not sure where the "XO" bus is at??

I would say you're in a bit of a pickle. I would start looking for a different transformer.

 

[benaround]

eletrick, I know just what you are talking about, had the same thing last year happen to

me. I ended up bolting the back lugs facing foward so no rear access was required. Luckily

the load gear was right next to the transformer so I ran gutter out the side of transformer

and used RHW-2 flexable conductors with compression eyeloops rated 90deg.C.

 

[RUWired]

I don't believe that article 110.26 applies to transformers. There is nothing that requires servicing while energized.

(A) Working Space. Working space for equipment operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), and (A)(3) or as required or permitted elsewhere in this Code.

Rick

 

[Jim W in Tampa]

Turn it 90 degrees and if that gives you 110.26 then your set to go.

 

[dcspector]

I don't believe that article 110.26 applies to transformers. There is nothing that requires servicing while energized.
Rick

Agreed Rick.

 

[eletrick]

Good Morning All,

Up date on this subject, “XO” is midway in the back.
Contractor provided 12” just so somebody can get in there to terminate.
Turning the thing will not work either (all pipe is underground....makes things worse, of course there are other options)
I agree there is nothing that requires work wile energized in the back.
I’m looking at 110.26 (1) (a) “Where rear access is required to work on nonelectrical parts………….30” shall be provided.”
Manufacturer states that after one year the lugs should be re-torqued (yea right. Like that is done in this world) and they state 6” for air flow. Unless there is a local code or the NEC.
And for the pictures…..batteries went poo and I have not bought new ones yet.

Thanks for the input, this is great site, I been a member since 2003 but usually just read, you folks are a hoot!!

 

[raider1]

I don't believe that article 110.26 applies to transformers. There is nothing that requires servicing while energized.

(A) Working Space. Working space for equipment operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), and (A)(3) or as required or permitted elsewhere in this Code.

Rick

Actually 110.26 applys to ALL electrical equipment. 110.26(A) applys to equipment that is likely to be worked on while energized.

110.26 Spaces About Electrical Equipment.
Sufficient access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment.

There is not specified working space required around electrical equipment that is not likely to be worked on while energized, but you are required to have sufficient working space.

Chris