Transformer / bonding

[liquidtite]

Does the nuetral xo get bonded to the frame of the transformer?
also is h1 h2 h3 always the primary ?

 

[iwire]

Does the nuetral xo get bonded to the frame of the transformer?

Usually.

also is h1 h2 h3 always the primary ?

No.

 

[liquidtite]

So their are exceptions when you don't have to bond xo to the gec.
The transformer is a 480 wye step down to 120/208 wye the transformer secondary is feeding a ups system. Would this transformers xo need to be bonded to the gec?
and is their a general rule to go by . Thanks for your time

 

[don_resqcapt19]

Take a look at 250.20.

 

[petersonra]

So their are exceptions when you don't have to bond xo to the gec.
The transformer is a 480 wye step down to 120/208 wye the transformer secondary is feeding a ups system. Would this transformers xo need to be bonded to the gec?
and is their a general rule to go by . Thanks for your time

If it is a wye primary and wye secondary (a somewhat unusual configuration) you would bond X0 on the secondary side to the GES. No bond on the primary side is ever needed.

There are exceptions to bonding the secondary X0 to the GES, but they would not appear to apply in this situation.

 

[Sparky3141]

I think a normal and common configuration would be: primary side EGC, SBJ, GEC, and SSBJ all landed on the (case bonded) terminal block inside the transformer. Bonding the system (neutral point) to the GEC is commonly known as a "solidly grounded system".

Again, normal configuration: H1,H2,H3 used for primaries but there are often other "H's" used for other input voltages.