4 ms·

It probably depends on local codes, but: >and the outlet was correctly grounded using my water heater as ground, according to my outlet tester. I don't think

by jaclaz 4y ago

It probably depends on local codes, but: >and the outlet was correctly grounded using my water heater as ground, according to my outlet tester. I don't think that grounding to a water heater (please read as to water plumbing) is correct.

marcus0x62 4y ago
Grounding to a cold-water pipe is pretty common in the US, and is allowed under certain narrow circumstances by the national code (subject, of course, to being disallowed by local codes.). Specifically: NFPA 70 250.52(A) Electrodes Permitted for Grounding. (1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductor(s) or jumper(s), if installed.
- coryrc 4y ago
  Even more so, it's usually mandatory to ground your panel to incoming water line when it is metallic. But that's for the electrical panel, not a single random outlet.
  - marcus0x62 4y ago
    Sure, but that’s about providing a ground path for the water line in case it becomes accidentally energized, not necessarily providing a ground electrode for the electrical service. In other words, you’d have to do that even if the metal water piping was not eligible to be used as a ground conductor: NFPA 70 250.104(A)(1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to any of the following: (1) Service equipment enclosure (2) Grounded conductor at the service (3) Grounding electrode conductor, if of sufficient size (4) One or more grounding electrodes used, if the grounding electrode conductor or bonding jumper to the grounding electrode is of sufficient size The bonding jumper(s) shall be installed in accordance with 250.64(A), 250.64(B), and 250.64(E). The points of attachment of the bonding jumper(s) shall be accessible. The bonding jumper(s) shall be sized in accordance with Table 250.102(C)(1) except that it shall not be required to be larger than 3/0 copper or 250 kcmil aluminum or copper-clad aluminum and except as permitted in 250.104(A)(2) and 250.104(A) (3).
dtgriscom 4y ago
Back in the day, I remember reading instructions on how to build some sort of electrical toy (a Tesla coil? can't remember). The circuit was 120VAC powered, with a hot side and a neutral side. The problem was that the neutral side was accessible to the user, and the plugs back then were unpolarized. So, if you plugged the "neutral" side of the plug into the "hot" side of the outlet, you would Have A Bad Day. The workaround: only wire the "hot" side to the plug, and connect the "neutral" side via a separate wire to a nearby radiator (presumably ground). That way, plug the plug in wrong and the toy wouldn't work, rather than becoming dangerously charged. Was it safe? Safe enough for back then...
- Gracana 4y ago
  Are you sure it didn’t have a normal plug, with a separate clip for a reliable chassis ground? I don’t see how the half plug with a neutral wire to a radiator would be “safe”, even when compared to a neutral-connected chassis with an unpolarized plug. “The hot side is accessible to the user” is still true, just remove the wire to the radiator, now it‘s at line potential.
- jaclaz 4y ago
  >Was it safe? Safe enough for back then... Yep, but back then we were much more reckless, just the other day there was a story on HN on amateur chemistry (dying or dead): https://news.ycombinator.com/item?id=33517520 https://news.ycombinator.com/item?id=33517520 About electricity, up to not so many years ago (here in Italy up to around 1990) electrical codes were fairly "open", with no ground/earth requirement, and up to the 1970's or so it was not so uncommon to have houses with external wires, see: https://news.ycombinator.com/item?id=29616691 https://news.ycombinator.com/item?id=29616691 How we (kids in the '60's and '70's) managed to largely survive these and all the other everyday risks (no helmet on motorbikes, no safety belts in cars, etc.) remains a mistery. But in the case reported here that today an electrician would ground an outlet to water plumbing, it would be - well before being forbidden - unthinkable of.
  - 13of40 4y ago
    > amateur chemistry Ah, those were the days. Back in the 80s my parents bought us a chemistry set from a thrift store that was probably 20 years old already. It was actually set up to teach some practical chemistry by providing a mystery substance and a set of reagents that would help you figure out what the substance was. Ten year old me just cut to the finish line and tasted the mystery substance - it was sugar.
Waterluvian 4y ago
My grandpa’s old home only had ground pin outlets in rooms with plumbing because they only wired them up to pipes. I could imagine some wild old codes allowing that kind of thing.

by jaclaz 4y ago

marcus0x62 4y ago

Grounding to a cold-water pipe is pretty common in the US, and is allowed under certain narrow circumstances by the national code (subject, of course, to being disallowed by local codes.). Specifically: NFPA 70 250.52(A) Electrodes Permitted for Grounding. (1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductor(s) or jumper(s), if installed.

coryrc 4y ago
Even more so, it's usually mandatory to ground your panel to incoming water line when it is metallic. But that's for the electrical panel, not a single random outlet.
- marcus0x62 4y ago
  Sure, but that’s about providing a ground path for the water line in case it becomes accidentally energized, not necessarily providing a ground electrode for the electrical service. In other words, you’d have to do that even if the metal water piping was not eligible to be used as a ground conductor: NFPA 70 250.104(A)(1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to any of the following: (1) Service equipment enclosure (2) Grounded conductor at the service (3) Grounding electrode conductor, if of sufficient size (4) One or more grounding electrodes used, if the grounding electrode conductor or bonding jumper to the grounding electrode is of sufficient size The bonding jumper(s) shall be installed in accordance with 250.64(A), 250.64(B), and 250.64(E). The points of attachment of the bonding jumper(s) shall be accessible. The bonding jumper(s) shall be sized in accordance with Table 250.102(C)(1) except that it shall not be required to be larger than 3/0 copper or 250 kcmil aluminum or copper-clad aluminum and except as permitted in 250.104(A)(2) and 250.104(A) (3).

dtgriscom 4y ago

Back in the day, I remember reading instructions on how to build some sort of electrical toy (a Tesla coil? can't remember). The circuit was 120VAC powered, with a hot side and a neutral side. The problem was that the neutral side was accessible to the user, and the plugs back then were unpolarized. So, if you plugged the "neutral" side of the plug into the "hot" side of the outlet, you would Have A Bad Day. The workaround: only wire the "hot" side to the plug, and connect the "neutral" side via a separate wire to a nearby radiator (presumably ground). That way, plug the plug in wrong and the toy wouldn't work, rather than becoming dangerously charged. Was it safe? Safe enough for back then...

Gracana 4y ago
Are you sure it didn’t have a normal plug, with a separate clip for a reliable chassis ground? I don’t see how the half plug with a neutral wire to a radiator would be “safe”, even when compared to a neutral-connected chassis with an unpolarized plug. “The hot side is accessible to the user” is still true, just remove the wire to the radiator, now it‘s at line potential.
jaclaz 4y ago
>Was it safe? Safe enough for back then... Yep, but back then we were much more reckless, just the other day there was a story on HN on amateur chemistry (dying or dead): https://news.ycombinator.com/item?id=33517520 https://news.ycombinator.com/item?id=33517520 About electricity, up to not so many years ago (here in Italy up to around 1990) electrical codes were fairly "open", with no ground/earth requirement, and up to the 1970's or so it was not so uncommon to have houses with external wires, see: https://news.ycombinator.com/item?id=29616691 https://news.ycombinator.com/item?id=29616691 How we (kids in the '60's and '70's) managed to largely survive these and all the other everyday risks (no helmet on motorbikes, no safety belts in cars, etc.) remains a mistery. But in the case reported here that today an electrician would ground an outlet to water plumbing, it would be - well before being forbidden - unthinkable of.
- 13of40 4y ago
  > amateur chemistry Ah, those were the days. Back in the 80s my parents bought us a chemistry set from a thrift store that was probably 20 years old already. It was actually set up to teach some practical chemistry by providing a mystery substance and a set of reagents that would help you figure out what the substance was. Ten year old me just cut to the finish line and tasted the mystery substance - it was sugar.

Waterluvian 4y ago

My grandpa’s old home only had ground pin outlets in rooms with plumbing because they only wired them up to pipes. I could imagine some wild old codes allowing that kind of thing.