Isolated Ground GFCI

[mdshunk]

Does anyone know if there are any IG GFCI receptacles being manufactured yet? If so, a link to the product would be great.

[Chicago Bender]

Nothing like this exists yet. You're right, it would be nice particularly for the GFCI's near hand washing sinks in a health care facility. The only way to do this at the moment is to use a GFCI breaker to protect a regular IG receptacle.

[Ohm1]

IG GFCI? :confused:

[Ron]

I'm interested in the application that would call for an isolated ground and GFCI receptacle.
Already most of the industry has stopped specifying IG circuits except maybe for audio studios, since it is essentially a waste of $.

[Unregistered]

Many locations in health care facilities are NEC required to be IG'd. A receptacle next to a hand washing sink in a doctor's exam room is one classic example of a receptacle that would need to be IG'd and GFCI'd.

[Ron]

I don't work in health care, but am always interested in learning. Could you help me with a code reference?

[mdshunk]

Article 517 is for health care facilities.

517.13 is the main section that relates to this thread.

I dread doing work that falls in the 500's, since this is odd work that is seldom done by me.

[Ohm1]

I would think that Having IG's would look more towards protection of sensitive equipment-- Seeing that IG series is perfect for sensitive electrical and electronic equipment?

[Ron]

I don't want to be a pest but I don't understand. 517.13(B) requires an insulated equipment grounding conductor to the device, not an isolated ground device. A standard hospital grade receptacle with a circuit that includes an insulated EGC would suffice. I would think that an IG receptacle as mentioned in the FPN for 517.16 would be a bad idea.

[Ohm1]

The IG design, an insulated greenwire is connected to the IG equipment ground pin's associated wiring terminal at one end, and at the upstream end, where it's directly and solidly terminated to equipment ground at the panelboard. Hence, the IG circuit is insulated from the panelboard downstream to the receptacle; due to the connection at the panelboard, however, it has not been isolated from equipment ground.

This brief explanation is useful and can be expanded to account for IG designs that are both directly connected to equipment at outlet level, and are upstream routed clear back to the service equipment before the direct and solid equipment grounding termination finally occurs.

However, if we used the term "isolated" in describing the IG design, there may be a tendency to think that the upstream end of the greenwire would be terminated to ground via an isolating impedance, such as a resistor, inductor, or even a capacitor. Or, that it was terminated to an earth grounding electrode that had no connection, except via the earth, to the site's service grounding electrode system. Also, when impedance is inserted in any of these manners into the equipment grounding conductor path, the NEC gets involved in several important ways, all of which are safety-related and ensure the impedance does not adversely limit fault current, create a fire or shock hazard, or both.

In short, "isolation" in the equipment ground path can become a can of worms, where "insulation" does not appear to do so.

You can start getting familiar by reviewing Sec. 250-74, Connecting Receptacle Grounding Terminal to Box, and related Ex. 4, along with the FPN.