Transformer bonding

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Shockedby277v

Senior Member
Location
Michigan
We have a medical grade isolation transformer 208v to 120v. The transformer isn’t bonded so we are getting funky voltages. X1 to ground is 60v, X2 to ground is 60v and X1 to X2 is 120v. Is X2 suppose to be bonded and act as our neutral? Or is X1? Where would I find this information from the manufacturer?
 

Shockedby277v

Senior Member
Location
Michigan
I read 517. It doesn’t indicate where to bond or not to bond at all in a iso xfmr. These look to be a typical install for operating rooms. This is just my first medical building and running into a lot of different items. We will have a start up on these so the tech should be able to advise I imagine. I will post how we end up handling it.
 

roger

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Staff member
Location
Fl
Occupation
Retired Electrician
I read 517. It doesn’t indicate where to bond or not to bond at all in a iso xfmr. These look to be a typical install for operating rooms. This is just my first medical building and running into a lot of different items. We will have a start up on these so the tech should be able to advise I imagine. I will post how we end up handling it.
You will not bond it period. You have 120 volts L- L meaning 60 volts per leg.

The circuits will be fed from two pole breakers and you will need a Line Isolation Monitor along with a miliammeter, you will need to use XHHW and no pulling compound. After the installation the room will need to be certified which takes multiple testing devices.

You should contract the equipment manufacturer or a BIO med testing company to do the certification.

Roger
 
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