[ponyboy]

This transformer will feed directly to a fused disconnect serving a pin and sleeve recep which is used to test a certain motor maybe a couple times a year. The question is do I need to ground this system? 250.20(B) appears to say I don't. Any ideas?

 

[Big John]

If it has to be ungrounded and has to be code compliant, you need to meet the requirements of 250.21. Put in some ground-detection lamps and call it good.

 

[knowledge29]

This same set up was in a plant i once worked in. Installed ground detectors and was good to go.

 

[ponyboy]

Would I need a secondary side equipment ground if I leave it ungrounded? The fused disconnect enclosure is grounded from the gutter it is nippled to

 

[Meadow]

Would I need a secondary side equipment ground if I leave it ungrounded? The fused disconnect enclosure is grounded from the gutter it is nippled to

Yes. Always run an EGC.

 

[ponyboy]

Yes. Always run an EGC.

seems simple enough yes. But this is a pretty weird setup for me. I've got two transformers side by side. One with a delta secondary and one with a wye secondary. The wye feeds a panelboard with nipples out the back through a wall into a gutter. The delta secondaries run through the wye panelboard into the gutter sand into a fused disconnect. They threw this delta bullchit at me last minute after I was pretty much done with the project. I got grounds going everywhere and needed some guidance. Thanks all

 

[ponyboy]

If it has to be ungrounded and has to be code compliant, you need to meet the requirements of 250.21. Put in some ground-detection lamps and call it good.

Got any one particular brand or setup you like for these?

 

[KGN742003]

Ground 1 corner, then you have a reference for the other phases to trip. It's usually B phase iirc.

 

[ponyboy]

Ground 1 corner, then you have a reference for the other phases to trip. It's usually B phase iirc.

That would be the typical approach yeah. But I have reasons why I'd rather leave it ungrounded

 

[Big John]

Got any one particular brand or setup you like for these?

No. The couple of times I've done it, I've made ground detectors from scratch. Listing schmisting.

You can get this from Platt for $360.

It's literally just three sets of series 120V LEDs connected in a wye. You could also make it for less than $30 with a few 250V neon lamps.

 

[Cl906um]

Just to be nosy, why ungrounded?