plug earth/ground checker by John Roberts

[JohnRoberts]

Can't ignore the irony of UL making it cost prohibitive to approve devices that fix known safety issues.

In the grand scheme of things UL is not a prohibitive cost factor for "real" businesses developing new products. Tooling up a slick package could cost a few times that, not to mention marketing a different new product.

UL is the stopper for me because the odds of "me" getting my investment back are about zero, and I've been unsuccessful finding  a deep pockets partner.
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In hindsight if that neon lamp screwdriver probe is UL approved, that tells me the simple 3 lamp outlet tester that doesn't work properly could be converted into a 4 lamp outlet tester that does reveal hot safety ground for a very manageable BOM cost increase (one more neon lamp, one more resistor, and one touch contact.)  I still predict a couple $10K worth of jawboning to get UL to change their written standard, since that screwdriver clearly does not provide 100M of insulation resistance, more like 100K ohm.

A 4 lamp outlet tester in the same < $10 retail would be a winner and perhaps save lives.  I need to run this up the right flagpole, and see if anybody salutes. Unfortunately these days that flagpole is probably in China.

That dangerous old 3 lamp tester is still an embarrassment to knowledgable electricians and a hazard to everybody else. The good news is that as time goes on there are less and less conversion of 2 wire houses to 3 wire outlets, but it is still not zero.

JR

 

[joaquins]

  Now we have non contact proves, EF detectors on HHDMM and with any of those (or the screw driver, we call "buscapolos" or polarity-finder) you can check for the live earth and correct neutral/hot connection. While neutral and hot swap are not as serious fault as  hot earth I understand why it should be also tested.

  Just pack 3 of those screwdrivers tied together in the human contact end and you have a better tester then the deadly one.

  Here we use a single 30mA GFCI ones for the entire hose, this usually ends in swapping hot and neutral, as hot insulation is compromised, nice hazard! The second time you need to do it you have to bypass the GFCI and get away fast. Then, I don't know how the GFCI cord you mention is internally connected, but it probably won't protect you from hot earth as it shouldn't interrupt the earth connection, at least with the ones we use here. 

  In industrial applications 300mA GFCI sensitivity is normal and even 3A in big places, as the big machines inevitable leak and you must allow for some. If everything is correctly grounded when something breaks it easily gets over 3A and the chasis voltage will always remain safe with a reasonably low ground impedance. This wouldn't protect a worker to go and grab the live wire, but they should know better. This will protect machines and human from faulty insulation touching all the exposed grounded metal.

JS

 

[cyrano]

Over here, we have 230 mA GFCI's on the entire system and 30 mA on the bathroom and kitchen.

I haven't seen a "hot ground" ever, but that doesn't exclude the possibility. As our ground lugs are protruding from the socket, it should get noted soon...

Reverse connection of live and neutral isn't a big problem either, as most nets are symmetrical to ground. Eg, you'll measure half of the voltage to ground from one connection.

The biggest problem is old installs that have no ground, no GFCI and no rules.

 

[JohnRoberts]

Over here, we have 230 mA GFCI's on the entire system and 30 mA on the bathroom and kitchen.

sensible.....  I have added (5mA) GFCI to kitchen, bathroom, and laundry room outlets.

I haven't seen a "hot ground" ever, but that doesn't exclude the possibility. As our ground lugs are protruding from the socket, it should get noted soon...

I've told this story before but back when I was working at Peavey we had a customer electrocuted by Peavey power amps plugged into a RPGB (reverse polarity bootleg ground) outlet. Peavey got sued, but UL was with us in court arguing that our UL approved products were safe, and the faulty house wiring was the problem.

Reverse connection of live and neutral isn't a big problem either, as most nets are symmetrical to ground. Eg, you'll measure half of the voltage to ground from one connection.

not in US. we have one 0V leg (neutral) and one 120V leg (line). That said inside products both line and neutral are insulated so reversal is not a safety issue.

The biggest problem is old installs that have no ground, no GFCI and no rules.

Like my house was?

JR

 

[JohnRoberts]

  Now we have non contact proves, EF detectors on HHDMM and with any of those (or the screw driver, we call "buscapolos" or polarity-finder) you can check for the live earth and correct neutral/hot connection. While neutral and hot swap are not as serious fault as  hot earth I understand why it should be also tested.

  Just pack 3 of those screwdrivers tied together in the human contact end and you have a better tester then the deadly one.

That would work, but adding a 4th neon lamp to the 3 lamp tester is cheaper and easier for marginal customers to understand.

  Here we use a single 30mA GFCI ones for the entire hose, this usually ends in swapping hot and neutral, as hot insulation is compromised, nice hazard! The second time you need to do it you have to bypass the GFCI and get away fast. Then, I don't know how the GFCI cord you mention is internally connected, but it probably won't protect you from hot earth as it shouldn't interrupt the earth connection, at least with the ones we use here. 

I also designed a backline safety device that musicians could use in series with their power outlet to protect them from stage power.  I combined a GFCI outlet with a 3 pole relay that could also disconnect ground if a hazard was detected.  In live performance situations the hot ground could also be coming from the front of house console, through the mic cable.  Opening up the stage power ground would be less dangerous, but still dangerous.

I never pursued this because musicians A) would never spend that kind on money for something that doesn't improve their "sound", and B) UL would never approve opening up a ground bond.

  In industrial applications 300mA GFCI sensitivity is normal and even 3A in big places, as the big machines inevitable leak and you must allow for some. If everything is correctly grounded when something breaks it easily gets over 3A and the chasis voltage will always remain safe with a reasonably low ground impedance. This wouldn't protect a worker to go and grab the live wire, but they should know better. This will protect machines and human from faulty insulation touching all the exposed grounded metal.

JS

Yup, accumulated leakage in combination with modest current thresholds (5mA) can make common GFCI marginal for some stage applications. But if your GFCI trips it is a good idea to figure out why.

JR

 

[JohnRoberts]

Since a picture is worth a thousand words, I modified my cheap 3 lamp tester that can't detect energized safety ground with a neon lamp and 100k resistor. (100k is well less than 1mA so more brightness is needed.)

It lights dimly when I touch the neon lamp lead when plugged into a faulty energized ground outlet.

This  indication light could safely be made brighter by feeding that dim light into the gate of an optical amplifier.

JR