GFI Questions

[S'mise]

Reading another post on gfci's sparked a few questions in my mind.

Why do gfci receptacles trip (need to be reset) whenever you loose power?
Are all receptacle type gfci's designed like that?

Why cant they be like the gfci cord on the end of a hair dryer? (dont have to be reset every time you plug them in?)

There are times that the latter would sure be handy, instead of using a gfci breaker.

 

[rcwilson]

None of my GFCI receptacles trip when I loose power. I have a lot around the house, garage and driveway.

I haven't heard of any of the ones at the plant's we build tripping on power outages, and there has been a lot of plant outages.

Maybe something is happening in your system to cause them to trip.

 

[Volta]

I think that was a particular vintage of GFCIs, new ones, and even older ones won't do that.

 

[S'mise]

Thanks, I hadn't realized the new one don't do that. Good to know

 

[Dennis Alwon]

I believe there was a vintage of male receptacle cord ends that would trip when the power went off. It is a safety think in shops and other areas where machines needed GFCI protection but you didn't want a table saw coming on when the power came back on.

I had one that was made for the construction site to protect workers from getting hurt. I believe there still are some out there.

 

[Twoskinsoneman]

Reading another post on gfci's sparked a few questions in my mind.

Why do gfci receptacles trip (need to be reset) whenever you loose power?
Are all receptacle type gfci's designed like that?

Why cant they be like the gfci cord on the end of a hair dryer? (dont have to be reset every time you plug them in?)

There are times that the latter would sure be handy, instead of using a gfci breaker.

If GFCIs did that these days that would be a deal breaker for me. There would be at least a couple coming out of my work shop.

 

[don_resqcapt19]

All of the older "portable" GFCIs did that, but I have never run across a GFCI intended for fixed use that did that. Portable GFCIs require "open neutral protection" and with the older ones they used a relay on the line side of the GFCI sensor to provide the open neutral protection. You had to push the reset each time the device was powered up to pull the relay in.

 

[Sierrasparky]

All of the older "portable" GFCIs did that, but I have never run across a GFCI intended for fixed use that did that. Portable GFCIs require "open neutral protection" and with the older ones they used a relay on the line side of the GFCI sensor to provide the open neutral protection. You had to push the reset each time the device was powered up to pull the relay in.

I've only seen that on portable cords and GFCI's. I have some myself.
I have seen homes hit by utility faults where the GFCI's were tripped.

 

[DTLight]

There has been a change in the UL standards for GFCI receptacles, where now they are required to have 'miswire' protection. These GFCI's can't be reset unless there is power supplied to the line terminals, and not the load terminals. Some of the designs to incorporate this protection include tripping whenever the power is interrupted.

http://tools.passandseymour.com/ProductKnowledge/course.cfm?course_sak=25&cur_page=0&cur_seq=0

 

[Sierrasparky]

There has been a change in the UL standards for GFCI receptacles, where now they are required to have 'miswire' protection. These GFCI's can't be reset unless there is power supplied to the line terminals, and not the load terminals. Some of the designs to incorporate this protection include tripping whenever the power is interrupted.

http://tools.passandseymour.com/ProductKnowledge/course.cfm?course_sak=25&cur_page=0&cur_seq=0

That is one reason that i refuse to use them on my jobs.... I love them at other peoples jobs though.