GFCI Protection

[BMacky]

I have installed some low-voltage light fixtures in a shower. They are step lights, vertically mounted, and the fixtures are wet-location rated. They flush mount to the finished surface (slate) and the transformers are remotely located. The primary side of the transformers are on the load side of the bath GFCI.

My question is does the transformer in any way isolate the monitoring circuitry of the GFCI from possible ground faults in the fixture on the low-voltage side?

Thank you.

 

[infinity]

GFCI protection is not required for lighting within a shower by the NEC, unless the lighting manufacturer requires GFCI protection none is needed. You could be trying for an extra level of safety. I don't see how the GFCI would actually work in this situation since the LV transformer is isolating the load from the GFCI sensing.

 

[Pierre C Belarge]

I have installed some low-voltage light fixtures in a shower. They are step lights, vertically mounter, and the fixtures are wet-location rated. They flush mount to the finished surface (slate) and the transformers are remotley located. The primary side of these transformers are on the load side of the bath GFCI.

My question is does the transformer in any way isolate the monitoring circuitry of the GFCI from possible ground faults in the fixture on the low-voltage side?

Thank you.

this is an interesting installation.
Do you have the model number of the fixtures?

 

[BMacky]

Fixture Specs

Fixture Specs

Hi Pierre,

The fixtures are B-K Lighting "Step Star" and were ordered with the low-voltage option using a GU-10 bulb at 20W. I am using the mfr recommended transformer (electronic) and these are remotely located and accessible in a non-wet location. Without the documentation in front of me, I cannot say for sure that the fixtures have a wet or damp location listing. I believe they do, but cannot reference the infomation at present.

The enclosure consists of a round bell box with bell box extension ring, gasketed. The cover (trim), which includes the bulb assembly, has a rubber gasket seal that seals the box completely. They are mounted in a wooden-stud wall and have thermal overload protection.

I had a rough inspection today and the inspector questioned the application, and referenced NEC articles for wet locations regarding switches and receptacles. Since this is a low-voltage appliacation, I don't feel they would apply.

Thanks for your query.


Bob

 

[BMacky]

Thanks, Trevor.

Yes, I felt I'd at least go with the GFCI protected power for the lighting, but thought afterwards that the transformer may isolate any irregularities in ground current.

Bob

 

[don_resqcapt19]

The GFCI will not see ground faults on the secondary side of the transformer, however they would see a primary to secondary fault that is combined with a secondary ground fault.
Don

 

[ZZZ]

Most every lamp I've seen with a G-10 base was 120 volts. A magnetic transformer will prevent a GFI from seeing a fault on the secondary, probably the same for electronic. I would sure want a document from the manufacturer stating the application is suitable for the listing, not just for the AHJ, but for liability reasons. The NEC is a minimum requirement, it will not magically save you from a wrongful death lawsuit. Absolutely use GFI's, they're cheap.