ATS Connection

[danilo]

Hi guys,

hope you can help me in my query and thanks in advance..

our electrical consultant has designed the electrical system of our new project to have two ATS at the secondary of 500kva,13.8kv/380v pad-mount transformer..is it allowed by the NEC to directly tap the normal side of ats to the secondary terminal of transformer?is there no need to install another main disconnecting means for the two ATS?

appreciate your help..thanks

 

[ron]

Re: ATS Connection

Is there a circuit breaker or fuses between the transformer secondary and the ATS?

 

[danilo]

Re: ATS Connection

Hi Ron,

thanks for the reply...there is no fuse or breaker connected in between the secondary of transformer and ATS except the normal breaker of ATS..same is true with the second ATS who is also connected to secondary side of the transformer.do you think its ok?

gracias Ron!

 

[sandsnow]

Re: ATS Connection

There is a listing category for ATS rated as service equipment.

When looking at this installation, go back to basics. Are the requirements for services in 230 being met?
Is there a service disconnect and overcurrent protection where the Code requires it?
Is the proper short circuit rating on the equipment?
Are the provisions for grounding being met?
Is there a main bonding jumper?

 

[danilo]

Re: ATS Connection

Yes, Art 230 has been complied including the KAIC rating of ATS, proper size of conductors etc...just in dilemma now if i would suggest to put a main disconnect at the secondary before the connection of ATS or not..just want to know code provisions on this,if none, then,i just wont comment on the proposed design..

appreciate your comment and suggestion

 

[sandsnow]

Re: ATS Connection

A disconnecting means on the line side of the ATS would allow it to be taken out for maintenance or repair more easily. The ATS itself has to be able to disconnect the building from all sources of supply. Req's in 225 and 230
As long as that is met, I don't see any violations.

 

[danilo]

Re: ATS Connection

thanks..by the way, the disconnecting means is at the line side of the 500kva pad mounted xformer and nothing at the secondary side of xformer..what is there at the secondary side is the two ATS already..i believe so that to service the ATS you have to shutdown the transformer thru its disconnect at the primary..basically, im avoiding unnecessary shutdown of the 500 kva xformer if its the ATS in trouble..that's why i want to find a provision in the code to support my argument that ATS should not be used as cut-out at the secondary side of xformer or a separate disconnecting means shall be installed at the secondary side of xformer other than the ATS.

thanks for your patience, guys..im quite dragging this too far..