[Anthony young]

Hey guys, I was just looking for a litle feedback on how most of you guys wire up the grounding on transformers. I have seen it done so many different ways. My personal preference is to connect my primary ground directly to the neutral bus on the transformer, then install my bonding jumper down to the grounding bus where I connect my secondary ground to structural steel along with the ground that goes directly to the panel that the transformer is feeding and also the grounds that tie to the bonding bushings. Like I said, I have seen the grounding wired up many different ways. I commonly see that a lot of people put all of their grounds including the primary all on the grounding bus that you have to install to the transformer casing and feed that ground bus with the jumper from the neutral bus. I personally like to connect my primary ground directly to my neutral bus and all other grounds to the grounding bus that I install at the bottom of the transformer. Really no matter how you do it, you are still connecting all of your grounds together and connecting them to the neutral bus via jumper. What are some of you guys thoughts and preferences on how you like to do it?

 

[glen1971]

I'm assuming you are talking about smaller transformers (15-112 kva-ish range). I take both the grounds from my primary and secondary feeders and terminate them under the ground for the case.. Then the bonding conductor comes in and I c-tap a tail onto it.. One end goes to the X0 and the other to the case ground.. Or I'l run it through the lug for the X0 then to the case...

 

[Anthony young]

Transformer grounding

Yes, I have done it that way as well. Since I have seen it done many different ways, usually what I do is if I'm wiring up a new transformer in an existing electrical room I'll just pull the cover off of one the existing transformers and wire the new one to match what was done on the existing transformers. So in your opinion its better to connect the primary and secondary grounds to the bus on the casing and jump that to X0? That sounds good to me, so that way the only things you have connected to X0 will be the neutral that is feeding the panelboard and the jumper to the ground bus that is attached to the casing. On my last job the plans had a wiring detail that showed how they wanted it wired. It called for the primary ground to go to the gound bus attached to the casing along with the ground feeding the panel and the grounds for the bond bushings but it called for the ground that goes up to the stuctural steel beam to be connected directly to X0 and not the ground bus. I didn't really like that so I connected my structural steel ground to the ground bus instead of X0 as it called for.

 

[drumnut08]

Hey guys, I was just looking for a litle feedback on how most of you guys wire up the grounding on transformers. I have seen it done so many different ways. My personal preference is to connect my primary ground directly to the neutral bus on the transformer, then install my bonding jumper down to the grounding bus where I connect my secondary ground to structural steel along with the ground that goes directly to the panel that the transformer is feeding and also the grounds that tie to the bonding bushings. Like I said, I have seen the grounding wired up many different ways. I commonly see that a lot of people put all of their grounds including the primary all on the grounding bus that you have to install to the transformer casing and feed that ground bus with the jumper from the neutral bus. I personally like to connect my primary ground directly to my neutral bus and all other grounds to the grounding bus that I install at the bottom of the transformer. Really no matter how you do it, you are still connecting all of your grounds together and connecting them to the neutral bus via jumper. What are some of you guys thoughts and preferences on how you like to do it?

. First off , you need to stop referring to XO in a dry type XFMR as the " neutral bus " . It's a tab for a lug at best . A neutral bus or bar is in a panel board or load center . I usually mount a multi position ground bar to the transformer casing under the core bonding strap or very close to it . I wire wheel off all the paint where the lug gets bolted down . Primary , secondary , and building steel grounds go to this bar . A bonding jumper either gets installed here or at the panel . I always do it here . This obviously goes between xo ( double barrel lug ) , and the common ground bar where all other grounds terminate . I don't think it's a very good idea taking your primary ground right to xo ? Look into the long multi position ground bars . 2 bolts and enough spaces for all your ground wires .

 

[Anthony young]

Yes Drumnut08, I agree, the correct terminology is X0. I do work all up and down the east coast and just depending on where I am everyone has their own lingo. I think I've heard it all and some of it is kind of silly or just wrong but I usually know what they're talking about. I just said that connecting my primary ground to X0 was my preference because thats the way I see it done most of the time which I understand doesn't necessarily make it correct but I have seen wiring details on the plans that call for it to be connected that way and also I've seen details that call for it to done differently. Thats why I just wanted a little feedback on how some of you guys do it. If the plans for the job I'm doing has a wiring detail I just follow that but that sometimes has me doing it a different way on every job. From the feeback I've got, from now on if my plans don't have a wiring detail I'm just going to connect all of my grounds to the ground bar at the casing and jump that to X0. I think that sounds like the best practice to me.