3 phase ground fault detector: I need some recommendations

This is probably right up a lot of your guys alley.

We've recently moved in to a new facility for our company (yay for massive unplanned company growth!) and much to my surprise, our 240v 3ph service is an ungrounded delta. I've only ever read about ungrounded service, I've never experienced one hands on. REALLY weird not having a ground reference and logging A phase to ground throughout the day and seeing readings vary from 365v to 90v. When we originally toured the place, I assumed it was a 240v 3ph center tapped delta. I was wrong. Oops. Anyhow..

The service for us, as well as two other tenants is off of a trio of 100kva cans that split between us. I'm not really thrilled about this, since if one tenant has a fault, it immediately becomes our problem as well. Shockingly, there is no ground fault detection in our facility, nor the company behind us.

So I need a recommendation.

I came across this module from ATC; https://www.marshbellofram.com/diversified-electronics/products/gfd-series-ungrounded-systems-alert/ but I'm looking for something at least with a relay output so I can connect a audible and visual indicator to it.

you may have to build your own. It would be very easy.

Bender makes ground fault detectors, I do see them frequently on drill rigs and most of them have a horn and strobe connected.

The defacto standard for the industry is a simple little relay from a company that used to be Instrument Transformer Inc. (ITI) called a BGFL. It's butt simple, reliable and rugged. You pair it up with a CT of the appropriate ratio for your service (up to 1200A) and wire it to a light if all you want is indication, or you can use a main CB with a Shunt Trip and trip your main (not recommended).

Years ago ungrounded Delta systems were the norm for some industries where shutting down the entire process causes more harm than good. So what you did was just have a way of letting you know there was a GF, but the plant kept running. Understand that the FIRST ground fault on an ungrounded delta system just means you go from ungrounded to corner grounded. Without indication, you may never even know. So at one steel mill I worked at years ago, we had 3 light bulbs on the wall of the electric shop and if one glowed brighter than the other, we knew we had a GF somewhere in the plant, so we would jump in a golf cart and run around looking for the smoke. I kid you not. It was akin to a "Damn the torpedoes, full speed ahead!" approach to plant management. Now the NEC says you must have ground monitoring and in some cases, protection (tripping) of you have an ungrounded delta, so you don't see new services like that any more. But legacy systems still exist all over.

These little BGFL relays are more reliable than the ground lights, and like I said, can be connected to a shunt trip if you are the nervous type. ITI was bought by GE years ago and rolled in with the Multilin group, but that same relay is available from Square D and Siemens, all made at the ITI factory in Florida.

http://www.gegridsolutions.com/products/specs/bgfl.pdf

jraef, in the manual for the BGFL relay it states that it is for a grounded AC system, so I don't think it will work with the system that the OP is dealing with.
However I did see the the three lights as simple ground fault indictators before, they just won't be able to trip an alarm of any kind.

We have this type of service on every ship I have worked on.
Some have the 3 indicator lights as previously mentioned.
Those are pretty easy to install....3 light bulbs and sockets and 3 transformers is all you need to get those going.
Problem with the lights for monitoring is that you don't really start picking up decent indication until you get a pretty good fault going. (IMO)

Some of the ships have fault meters and these will register minor faults and the meter will increment as the intensity of the fault increases. These also have relay outputs so you could connect it to an alarm if you wanted.

You have to watch what you use in your plant with this type of system though.
A lot of power strips, UPS systems, battery charging equipment and surge suppressors reference ground and if you use these your fault meter will see the ground reference. This will have you running around chasing faults the whole day long.....its really fun. A portion of my job consist of keeping these meters out of the red.

We always have some minor faults on the system, (ups, etc) just have to keep diligent and try to weed them out.
When you get a major fault you need to find it quick, because if another phase ground faults at the same time things can get interesting.
Have had a dozen or so UPS, and multiple electronics smoke all at the same time when this happens.
We get major faults all the time also since our factory is full of electrical equipment, has sea water pumps flooding the decks the entire time we are in production and they use salt water for doing most of the wash down also.
(100 third world processors spraying salt water all over everything.....what could go wrong?)

The equipment we use is made by Dief.
I could look and get you some part #s if you want to go that route.

We actually have both the lights and the meters on the ship I am on now.
Lights on the 480v and meters on the 240v and 120v distribution.

BCS

start with a few simple lamps, and as the sailor says you can buy a gfds from a marine supplier, or me i have them in shop