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Why not one, large GFCI?

12:58AM | 11/23/02

Member Since: 11/02/02
69 lifetime posts

Why not one, large GFCI?

Here's a question I've always wondered about. GFCI circuit-breakers exist, right? So why not just get one, as in a GFCI main, to protect your whole house? I'm guessing a bit here at the answer, but I wonder whether the greater the load that hangs off of one of these things, the less sensitive they can be. And that brings me to a second question: is there an inherent advantage to using two or three GFCI outlets rather than one GFCI breaker?

Tom O

02:16AM | 11/23/02

Member Since: 09/17/02
477 lifetime posts

A GFCI breaker trips at about 5/1000 of an amp. Since there is no such thing as a perfect insulation, you will eventually have enough wire installed so that the normal leakage current exceeds the 5/1000 of an amp & you are standing in the dark.

You cannot go to a higher trip level. That level was selected to protect life & a higher value would not do the job.

GFCI outlets- you can buy 5 or 6 of them for the cost of one GFCI breaker. Also, it is much more convenient to have them near the point of use so you can reset them and, more importantly, test them once a month.

Tom

JonathanGennick

07:58AM | 11/23/02

Member Since: 11/02/02
69 lifetime posts

Thanks Tom. Your explanation is very clear, and it makes a lot of sense, actually.

Electrical Inspector

12:17PM | 11/23/02

Member Since: 09/27/02
73 lifetime posts

the 'whole house' protective method is used in Europe, at 300ma i believe.

There are pro's and con's ( we have discussed it) , yet overall i must tip my hat to the safer method there....

Tom O

03:29AM | 11/24/02

Member Since: 09/17/02
477 lifetime posts

How does a 300 ma GFI protect me from receiving a fatal shock?

DaveB.inVa

08:34AM | 11/24/02

Member Since: 07/28/02
4 lifetime posts

Theirs are not meant for protection of personell. Most of Europe is running at 240v to ground, these ground fault devices are to prevent fire causing arcs much like the ground fault devices that are installed on certain 277/480 services here in the United States.

Tom O

12:53PM | 11/24/02

Member Since: 09/17/02
477 lifetime posts

Then these whole house GFI's would require supplemental GFI protection with additional GFI breakers or GFI receptacles. This brings us back to where we started with the additional expense of a GFI main breaker.

Electrical Inspector

02:12AM | 11/25/02

Member Since: 09/27/02
73 lifetime posts

like i said, pro's and con's guys.

as 210.12 grows to a more 'encompasing' requirement ,i believe comparissons to European standards will be more prevalant

rpxlpx

02:22AM | 11/25/02

Member Since: 03/13/00
1675 lifetime posts

One good thing about having them on individual circuits is that only a small area of the house goes dead and then it's much easier to diagnose the problem.
If your whole house goes "dead" all at once, you wouldn't know if it's the whole-house GFCI or a transformer down the road that went out.
If the problem is persistent, or takes time to find, you would still want to have your HVAC, etc. working.

[This message has been edited by rpxlpx (edited November 25, 2002).]

JasonP

11:59AM | 11/27/02

Member Since: 11/16/02
64 lifetime posts

Greetings All,

As some have mentioned, there are some circuts that are dedicated like the refer and furnace.

If you go on a vacation and your power trips, you could come home to a real disaster!(spoiled food and frozen pipes)

I educated one builder on the benifits of GFI outlets in the rooms that needed them by trip testing every outlet while he ran up and down the stairs to reset the breakers.

The next house he built had them in the rooms!

Best regards,
Jason