Residential 2 wire recptacles
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peter d
Senior Member
- Location
- New England
Re: Residential 2 wire recptacles
If I didn't use the surge strip, all I would need is a 2 wire receptacle.
I am not sure how a TVSS works but I would hope it would offer protection without a ground.
The cord coming off the laptop power supply is a 2 wire cord. It is then plugged into a surge protected outlet strip, which is plugged into a grounded outlet.
If I didn't use the surge strip, all I would need is a 2 wire receptacle.
I am not sure how a TVSS works but I would hope it would offer protection without a ground.
allenwayne
Senior Member
Re: Residential 2 wire recptacles
Simular to a breaker lock out for an a/c that the pull out is behind but above the unit,if the service tech for the a/c doesn`t utilize the lock out protection well it`s his bad.110.26 deals with energized equiptment.Not energized well 110.26 does not apply.Sure I am opening the flood gates on this one
Simular to a breaker lock out for an a/c that the pull out is behind but above the unit,if the service tech for the a/c doesn`t utilize the lock out protection well it`s his bad.110.26 deals with energized equiptment.Not energized well 110.26 does not apply.Sure I am opening the flood gates on this one
Re: Residential 2 wire recptacles
Hi Guys ,
This seems to be a good thread to apply this question to:
What about 120v computor equipment that requires a three prong (grounding) receptacle. Seems to me that a 'grounding conductor' would be necessary since the GFI would only be good for protection of personell.
Mike
Hi Guys ,
This seems to be a good thread to apply this question to:
What about 120v computor equipment that requires a three prong (grounding) receptacle. Seems to me that a 'grounding conductor' would be necessary since the GFI would only be good for protection of personell.
Mike
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Re: Residential 2 wire recptacles
If the intent is as it's put in the handbook, I think 250.130(C) needs a drastic revision, as "any accessible point" sounds like any accessible point, not a point within 5' of the entrance to the building.
That's weird.
But the conductor in question is performing a bonding function, not a grounding function. This conductor isn't performing the duties of the water bond set forth in 250.52.
If the intent is as it's put in the handbook, I think 250.130(C) needs a drastic revision, as "any accessible point" sounds like any accessible point, not a point within 5' of the entrance to the building.
That's weird.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: Residential 2 wire recptacles
George,
I'm missing what you're seeing in the language.
When I look at the text of 250.130(C)(1) & (2), I think of a duplex receptacle (say it's on a #14 copper conductors) and I want to add an EGC from the receptacle to. . .well, to the choices I am given in 250.130(C).
250.130(C)(1) & (2) lets me connect to the GES or the GEC.
So I get a piece of #14 copper and attach one end to the receptacle ground screw and decide the metal water pipe system is the easiest to run to.
Now, that piece of #14 is a conductor, period. It is included in 250.118. I look at the local cold water pipe, say, 20 feet inside the house from the first 5 feet. . .it's all metal and it's bonded. . .nice and conductive. . .why can't I use it as a conductor that is at least as good as the #14 EGC coming from my receptacle? For one thing, water pipe isn't included in 250.118. So I am left with the part of the water pipe that the NEC says is part of the GES and that can be uses as a GEC. . .the first 5 feet.
George,
I'm missing what you're seeing in the language.
When I look at the text of 250.130(C)(1) & (2), I think of a duplex receptacle (say it's on a #14 copper conductors) and I want to add an EGC from the receptacle to. . .well, to the choices I am given in 250.130(C).
250.130(C)(1) & (2) lets me connect to the GES or the GEC.
So I get a piece of #14 copper and attach one end to the receptacle ground screw and decide the metal water pipe system is the easiest to run to.
Now, that piece of #14 is a conductor, period. It is included in 250.118. I look at the local cold water pipe, say, 20 feet inside the house from the first 5 feet. . .it's all metal and it's bonded. . .nice and conductive. . .why can't I use it as a conductor that is at least as good as the #14 EGC coming from my receptacle? For one thing, water pipe isn't included in 250.118. So I am left with the part of the water pipe that the NEC says is part of the GES and that can be uses as a GEC. . .the first 5 feet.
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Re: Residential 2 wire recptacles
I understand your concept, but I'm left confused by experience.
If I run my water bond to 1' from the entrance to the building, and the metering equipment is at two feet, I will fail a house if I do not bond the far side of the water meter to the side closer to the entrance. Every time.
If I have a jetted tub, and the entire water system is copper, I am permitted to bond my tub to the cold water pipe at the tub. Every time.
So, it leaves me wondering if "GES" or "GEC" is accurate, or a fast and dirty way of saying "water pipe" without realizing the restriction that it is then put under, the 5' rule.
I just see "any accessible point" taunting us with either a lie, or a silly way of saying within five feet of entrance, if accessible. If you're right, and I am by no means saying you're not, then this portion needs revision, because everybody I know reads it wrong.
The original code, before it sends you hither thither and yon, should say something meaningful before it sends you on the hunt. This one says something totally different before it sends you to 250.50, which sends you to 250.52, which never directly addresses bonding, because it's focus is grounding.
Your point about 250.118 is valid, but if you were to add (just for our purposes here) 230.130(C)(6), "Any accessible point on a metallic water piping system that is connected to the GES", 250.118 flies right out the window. 250.130 would then have expressly permitted what 250.118 didn't expressly permit, but didn't forbid. As it has been commonly interpreted in this fashion, I'd say we need some rewriting, either way.
Given your handbook reference, I can see which way it would go.
But...is there a hazard/body count?
I understand your concept, but I'm left confused by experience.
If I run my water bond to 1' from the entrance to the building, and the metering equipment is at two feet, I will fail a house if I do not bond the far side of the water meter to the side closer to the entrance. Every time.
If I have a jetted tub, and the entire water system is copper, I am permitted to bond my tub to the cold water pipe at the tub. Every time.
So, it leaves me wondering if "GES" or "GEC" is accurate, or a fast and dirty way of saying "water pipe" without realizing the restriction that it is then put under, the 5' rule.
It seems like everybody I know, sparky, inspector or otherwise, understands this issue the way I do. My point is, is using the water pipe beyond 5' a legitimate hazard, or code massaging for code's sake?
I just see "any accessible point" taunting us with either a lie, or a silly way of saying within five feet of entrance, if accessible. If you're right, and I am by no means saying you're not, then this portion needs revision, because everybody I know reads it wrong.
The original code, before it sends you hither thither and yon, should say something meaningful before it sends you on the hunt. This one says something totally different before it sends you to 250.50, which sends you to 250.52, which never directly addresses bonding, because it's focus is grounding.
Your point about 250.118 is valid, but if you were to add (just for our purposes here) 230.130(C)(6), "Any accessible point on a metallic water piping system that is connected to the GES", 250.118 flies right out the window. 250.130 would then have expressly permitted what 250.118 didn't expressly permit, but didn't forbid. As it has been commonly interpreted in this fashion, I'd say we need some rewriting, either way.
Given your handbook reference, I can see which way it would go.
But...is there a hazard/body count?
Re: Residential 2 wire recptacles
Nearly all the old two wire receptacles I have pulled were in metal boxes with NO grounding wire and NO conduit. Now suppose a hot conductor comes into contact with the steel box. Nothing happens except the box, strap and cover plate screw become energized, possibly for a long time without being detected. Now someone comes along and plugs in a cheater and screws in the little tab to the cover plate screw. Then they plug in a metal appliance, say a dishwasher or microwave oven. Now, thru the connection to the cover plate screw, the metal appliance becomes energized, creating a worse problem than if they would have just broke off the third pin and plugged it in.
I don't think that tab is such a good idea, considering that in most cases a grounding path back to the panel does not exist.
Nearly all the old two wire receptacles I have pulled were in metal boxes with NO grounding wire and NO conduit. Now suppose a hot conductor comes into contact with the steel box. Nothing happens except the box, strap and cover plate screw become energized, possibly for a long time without being detected. Now someone comes along and plugs in a cheater and screws in the little tab to the cover plate screw. Then they plug in a metal appliance, say a dishwasher or microwave oven. Now, thru the connection to the cover plate screw, the metal appliance becomes energized, creating a worse problem than if they would have just broke off the third pin and plugged it in.
I don't think that tab is such a good idea, considering that in most cases a grounding path back to the panel does not exist.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: Residential 2 wire recptacles
Hey George,
Up through the 1990 NEC there was clear permission to use the water pipe.
Minnesota has enforced the change for new installations since the 1993 went into effect.
Perhaps there is a Colorado exception to the NEC on this issue?
[ March 03, 2005, 11:35 PM: Message edited by: al hildenbrand ]
Hey George,
Up through the 1990 NEC there was clear permission to use the water pipe.
Then the 5' length limit was added to 250-80(a) and became 250-81 in the 1993 NEC
The 1993 NECHandbook adds the following text after 250-50 Exception:
I don't have any idea what statistics of injury or death are.
Minnesota has enforced the change for new installations since the 1993 went into effect.
Perhaps there is a Colorado exception to the NEC on this issue?
[ March 03, 2005, 11:35 PM: Message edited by: al hildenbrand ]
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Re: Residential 2 wire recptacles
My guess is, nobody noticed?
That does help with understanding a lot. Thanks, Al!
Edit to add:
Here's a thought: Since the only time this really comes into effect is on older houses built prior to 1993, wouldn't the closest water pipe be considered part of the GES, since 90% of the house is wired to pre-1993 code? The existing receptacles (if they had awareness ) would view the water pipe as part of the GES.
Kind of a weird thought, had to get that out there while it was fresh in mind. Now I'm late for work.
[ March 04, 2005, 08:31 AM: Message edited by: georgestolz ]
My guess is, nobody noticed?
That does help with understanding a lot. Thanks, Al!
Edit to add:
Here's a thought: Since the only time this really comes into effect is on older houses built prior to 1993, wouldn't the closest water pipe be considered part of the GES, since 90% of the house is wired to pre-1993 code? The existing receptacles (if they had awareness
) would view the water pipe as part of the GES.Kind of a weird thought, had to get that out there while it was fresh in mind. Now I'm late for work.
[ March 04, 2005, 08:31 AM: Message edited by: georgestolz ]
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: Residential 2 wire recptacles
George,
You really are a troublemaker, aren't you.
I actually like the twist (twisted-ness?) in your thought, there.
Let me rephrase:
Is the metal water piping of a dwelling built prior to the enforcement of the 1993 5 foot limit grandfathered in as conductor?
I'd say yes, for the purposes of existing installations, installed prior to the enforcement of the 1993 NEC.
However, when I alter an existing ungrounded receptacle outlet, today, by replacing the receptacle with a grounded receptacle and add an EGC, then that is a new installation and it is governed by the current Code in effect today (2002 NEC in my area), and the 5 foot limitation applies.
--*--
The one real problem left unresolved, in my mind, concerns the use of the metal water pipe that is grandfathered in for all the pre-1993 installations. They just sit there. . .time passes. . .then someone alters the water piping and uses nonconductive parts, or a section of old pipe is cut off and abandoned in place. This someone has no knowledge of whether the metal pipe is used as a conductor, and, as a result of plumbing work, floats part of the electrical system, potentially the GEC itself. It's a gamble whether an inspection of some sort will catch the missing ground first, or a mishap will occur.
'Course, the replacement of the water main coming from the municipal water system to the house will create the same issue.
Ultimately, I won't be surprised to see more restrictions on the use of metal water pipe systems as part of the GES introduced over the coming Code cycles.
George,You really are a troublemaker, aren't you.
I actually like the twist (twisted-ness?) in your thought, there.
Let me rephrase:
Is the metal water piping of a dwelling built prior to the enforcement of the 1993 5 foot limit grandfathered in as conductor?
I'd say yes, for the purposes of existing installations, installed prior to the enforcement of the 1993 NEC.
However, when I alter an existing ungrounded receptacle outlet, today, by replacing the receptacle with a grounded receptacle and add an EGC, then that is a new installation and it is governed by the current Code in effect today (2002 NEC in my area), and the 5 foot limitation applies.
--*--
The one real problem left unresolved, in my mind, concerns the use of the metal water pipe that is grandfathered in for all the pre-1993 installations. They just sit there. . .time passes. . .then someone alters the water piping and uses nonconductive parts, or a section of old pipe is cut off and abandoned in place. This someone has no knowledge of whether the metal pipe is used as a conductor, and, as a result of plumbing work, floats part of the electrical system, potentially the GEC itself. It's a gamble whether an inspection of some sort will catch the missing ground first, or a mishap will occur.
'Course, the replacement of the water main coming from the municipal water system to the house will create the same issue.
Ultimately, I won't be surprised to see more restrictions on the use of metal water pipe systems as part of the GES introduced over the coming Code cycles.
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Re: Residential 2 wire recptacles
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Residential 2 wire recptacles
Hey all How about if someone were to label the water pipe at every available location with a warning label that warns that
"replacing any water pipe in this structure with a non-conductive piping, will cause the electrical system to be non-grounded which can lead to a shock hazard! Please contact a qualified electrician to make the proper connection to the grounding system if the water pipe must be replaced"
250.52 Exception allows this in industrial and commercial buildings or structures where conditions of maintenance and supervision ensure that only qualified persons service the installation?
I just wonder if this could be adapted to be used in a dwelling? Telco's already use a warning like this when they attach there grounding connection to the electrode system.
Hey all How about if someone were to label the water pipe at every available location with a warning label that warns that
"replacing any water pipe in this structure with a non-conductive piping, will cause the electrical system to be non-grounded which can lead to a shock hazard! Please contact a qualified electrician to make the proper connection to the grounding system if the water pipe must be replaced"
250.52 Exception allows this in industrial and commercial buildings or structures where conditions of maintenance and supervision ensure that only qualified persons service the installation?
I just wonder if this could be adapted to be used in a dwelling? Telco's already use a warning like this when they attach there grounding connection to the electrode system.
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