Got Knocked on my butt today. UPDATE: Non Contact Voltage Detector

[pecmsg]

Ok, Here is the code referenced. I think the key thing to note is the second bullet point, "the load must be handled by a 20 A breaker". That would limit the amount of current the raceway would have to carry. That would also be why most conduit has a ground wire in it.

https://www.electricallicenserenewal...ectionID=269.0

The conduit must be terminated in listed fittings.
I take this to mean Grounding Bushings!

[Sapote]

I see units on a regular basis where no ground wire has been pulled.

Does it have a metal conduit served as equipment grounding?

[pecmsg]

Does it have a metal conduit served as equipment grounding?

Reread post #200!

Ok, Here is the code referenced. I think the key thing to note is the second bullet point, "the load must be handled by a 20 A breaker". That would limit the amount of current the raceway would have to carry. That would also be why most conduit has a ground wire in it.

https://www.electricallicenserenewal...ectionID=269.0

[Joab]

Ok, Here is the code referenced. I think the key thing to note is the second bullet point, "the load must be handled by a 20 A breaker". That would limit the amount of current the raceway would have to carry. That would also be why most conduit has a ground wire in it.

https://www.electricallicenserenewal...ectionID=269.0

That’s for FMC or LTFMC (flexible metal conduits)

Rigid metal piping systems are considered an equipment grounding conductor, it can be used at any length or amperage without limitation. It’s no different from a wire type equipment grounding conductor according to the NEC

[Joab]

The conduit must be terminated in listed fittings.
I take this to mean Grounding Bushings!

No, it means just what it says. A lot of conduit fittings are not necessarily listed at all, they are just made to standards. A fitting used for equipment grounding in a flexible metal raceway has to have a NRTL listing


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[pecmsg]

Not in my neck of the woods!

[pecmsg]

No, it means just what it says. A lot of conduit fittings are not necessarily listed at all, they are just made to standards. A fitting used for equipment grounding in a flexible metal raceway has to have a NRTL listing


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Let me ask you

Why is BX cable no longer produced?

answer...No ground Conductor, its been replaced with MC cable

[stumpdigger]

Let me ask you

Why is BX cable no longer produced?

answer...No ground Conductor, its been replaced with MC cable

(In Chicago) BX was "outlawed" because the wire was already pulled thru it. This caused many faults due to inept DIY cutting through the wire insulation. The other problem was that HO would run BX to a switch; in the case of my dumb ass middle brother, he would ground everything!

[WT70]

EMT and Ridgid conduit can be used as the equipment ground conductor according to code as long as installed correctly.

But, personally, I’d run a wire as an added measure of safety... ...what happens if a conduit connection happens to pull apart, thereby losing the path back for fault protection?


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[pecmsg]

EMT and Ridgid conduit can be used as the equipment ground conductor according to code as long as installed correctly.

But, personally, I’d run a wire as an added measure of safety... ...what happens if a conduit connection happens to pull apart, thereby losing the path back for fault protection?


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Exactly!

[pecmsg]

(In Chicago) BX was "outlawed" because the wire was already pulled thru it. This caused many faults due to inept DIY cutting through the wire insulation. The other problem was that HO would run BX to a switch; in the case of my dumb ass middle brother, he would ground everything!

MC Cable is still the same except with another conductor yet us allowed, Can you explain this?

[Scoobie]

Was checking a three ton condensing unit today and as soon as I went to unscrew the cover I literally got quite the shock. I shut the breaker and started checking. The unit only had two wires going to it, therefore no ground. The Compressor didn’t check out grounded but it was open. I didn’t check the condenser motor , But the motor was working and drawing normal Amps. Can you even check for a ground if the unit isn’t grounded?

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I haven’t read this entire post so forgive me if this has been discussed.

I’m assuming this was the outdoor section of a split system. If you got zapped at the outdoor unit, the indoor and outdoor units are neither grounded, right? I think so since copper pipe runs between them. So the short could have been in the indoor or outdoor section. You could have turned the disconnect off, and still got popped from the indoor short, going down the refer pipes, through the cond unit, and through you to the earth.

[RLJN]

Scoobie's posting does explain why everything should be bonded to the system's grounding electrode conductor. Without each AH, AC, or furnace properly grounded/bonded that shock could have come from various places. Even a bare "hot" wire touching the ductwork could have sent that stray current out to the AC thru the AH/furnace via the ACR lines.
So you could have gotten "zapped" at any of these other points. But if each item is grounded/bonded then a CB somewhere would trip if the fault current was high enough.


I think that "BX" is a trade name for AC cable. The outer metal jacket of AC cable is supposed to qualify as a ground conductor if installed correctly. It has/had a 16 gauge bare aluminum wire that is supposed to be folded back under the cable connector insuring continuity of the ground path.......this has to me always seemed flakey and no one has really come up with a true explanation....some say you do not have to fold back and bond the 16 gauge AL etc......I do not trust any flex connector to provide proper grounding (IMO)

MC has a green grounding conductor. The outer sheath of MC is not considered a proper grounding path. MC cable is much easier to strip/work with, a sharp knife could score the sheath and then a quick bend would snap the AL sheath and you slide it off.

AC cable may have a green grounding conductor and the outer sheath is considered a redundant ground path and IIRC AC cable, with ground, may be used in medical patient care areas that require redundant grounding.

The early AC was some miserable shet to work with, it had bad insulation that after some years would just fall off.....easy to nick when removing sheath even with the proper cutter.
I would replace it when possible.

MC is impressive looking but still has the same protection requirements of Romex.
For instance if below 6 1/2' above the floor it must be drilled thru studs or mounted on a guard board... Flexible metal conduit (even aluminum) requires less protection even though it looks about like MC.

I have remodeled several jobs where the 1/2" EMT was the grounding means.
I had a collection of pictures and burned fittings/locknuts that failed as a grounding means. Some EMT connectors are weak physically and if broken from bad install and supports will lose the ground path.
For probably the last 30 years I have run a green ground wire in all raceways, even though not required. Every box along this path is grounded with the green screw.

There are "forensic analysis" articles in magazines....there are lawyers everywhere, they will hire electrical pros to analyze for any liability.

Over 40 years I have read the code Q&A's in ECM and EC magazines. It is amazing of the disputes with an inspector about needing a ground wire in that less than 6' of flex.
For the time spent with the argument and possible reinspection fees it seems like the best thing would be to include the ground wire......it is something of a scrap length of copper....you could strip the conductor if you do not have the green wire....(I have done that....sometimes just the ends that are visible....but let's not go there).

I started wiring houses for a contractor in 1969, we had to drag in 2 boxes of each type of romex. Only the outlets got cable with a ground wire....it was just a cheesy # 16 copper.
All the switching and light got cable without ground wire.
The EC was cutting cost to the bone...but everything was inspected and up to code.

Just to show you how things have changed in a short?? few years....God now I feel old!

[Joab]

Scoobie's posting does explain why everything should be bonded to the system's grounding electrode conductor. Without each AH, AC, or furnace properly grounded/bonded that shock could have come from various places. Even a bare "hot" wire touching the ductwork could have sent that stray current out to the AC thru the AH/furnace via the ACR lines.
So you could have gotten "zapped" at any of these other points. But if each item is grounded/bonded then a CB somewhere would trip if the fault current was high enough.


I think that "BX" is a trade name for AC cable. The outer metal jacket of AC cable is supposed to qualify as a ground conductor if installed correctly. It has/had a 16 gauge bare aluminum wire that is supposed to be folded back under the cable connector insuring continuity of the ground path.......this has to me always seemed flakey and no one has really come up with a true explanation....some say you do not have to fold back and bond the 16 gauge AL etc......I do not trust any flex connector to provide proper grounding (IMO)

MC has a green grounding conductor. The outer sheath of MC is not considered a proper grounding path. MC cable is much easier to strip/work with, a sharp knife could score the sheath and then a quick bend would snap the AL sheath and you slide it off.

AC cable may have a green grounding conductor and the outer sheath is considered a redundant ground path and IIRC AC cable, with ground, may be used in medical patient care areas that require redundant grounding.

The early AC was some miserable shet to work with, it had bad insulation that after some years would just fall off.....easy to nick when removing sheath even with the proper cutter.
I would replace it when possible.

MC is impressive looking but still has the same protection requirements of Romex.
For instance if below 6 1/2' above the floor it must be drilled thru studs or mounted on a guard board... Flexible metal conduit (even aluminum) requires less protection even though it looks about like MC.

I have remodeled several jobs where the 1/2" EMT was the grounding means.
I had a collection of pictures and burned fittings/locknuts that failed as a grounding means. Some EMT connectors are weak physically and if broken from bad install and supports will lose the ground path.
For probably the last 30 years I have run a green ground wire in all raceways, even though not required. Every box along this path is grounded with the green screw.

There are "forensic analysis" articles in magazines....there are lawyers everywhere, they will hire electrical pros to analyze for any liability.

Over 40 years I have read the code Q&A's in ECM and EC magazines. It is amazing of the disputes with an inspector about needing a ground wire in that less than 6' of flex.
For the time spent with the argument and possible reinspection fees it seems like the best thing would be to include the ground wire......it is something of a scrap length of copper....you could strip the conductor if you do not have the green wire....(I have done that....sometimes just the ends that are visible....but let's not go there).

I started wiring houses for a contractor in 1969, we had to drag in 2 boxes of each type of romex. Only the outlets got cable with a ground wire....it was just a cheesy # 16 copper.
All the switching and light got cable without ground wire.
The EC was cutting cost to the bone...but everything was inspected and up to code.

Just to show you how things have changed in a short?? few years....God now I feel old!

Nice post!

BX never really existed in a sense. It was a trade term for a cable product that was never listed by a NRTL. It had multiple problems, including being a poor ground. But hey, I still see a lot of it in use 50 years later.

AC cable was the listed product that followed ( or maybe a more expensive product that coincided for a while?) Still use a lot of AC cable in hospitals, we just call it MC-AP and add an additional ground wire to satisfy redundant grounding requirements in patient care areas.

The shorting wire inside the armor is to make sure the armor is connected in a straight line, so that current doesn’t have to spiral around following the armor, which would increase the length and resistance by a lot. It doesn’t matter what you do with the shorting wire at the connections, it’s job is to keep the armor continuous.

I pull equipment grounding wires in almost everything, but I’m thinking about changing that. Most places it’s a good idea, but sometimes I think it might be a waste of time. If we’re running EMT on the ceiling of a metal framed structure 25’ in the air, what am I gaining by adding a wire type EGC? The chances of physical damage is very small, but even if the it does get damaged, that pipe is literally bonded to the steel structure every ten feet. There is really no way that pulling a wire is making that installation more safe.

My point is that all of us working with wiring systems need to take the effort to understand what we are trying to accomplish and how to make sure it’s safe.

I’ve seen some really nice conduit jobs done without any wire type grounds pulled that were very safe because the installation of the grounding system as a whole was done to code and the installer understood the concept of what he was doing.

I’ve also seen installations that were quite dangerous where a wire type EGC was pulled everywhere, but the installer didn’t understand how to terminate it, or didn’t install the rest of the grounding correctly.

[Unlimited1]

I deal with a ton of RTUs with the 208v 0-#4 3ph main power cables coming under it, across the compressor section, not in anything, into the disconnect and then into the lower contactor for distribution. A few gems with be the unshielded tstat wires running right next to it. There is always 1 power wire rubbing against the compressor door...I use 2” pvc that I put on my table saw to make a 5/8” slot..power off at the breaker . Cut pvc to length and put man power wires inside . A few zip ties keep it inside...with dollops of silicone at the zip ties..you may wonder why...in short fashion! Not going to remove a bad compressor to accidentally hit/pinch Live high incoming voltage ..Call me paranoid but I’m still alive...only a fool takes that chance...

IMHO, those installers should be hanged to allow that! Next to the thwn clear coat vinyl peeling off from also being exposed to the outside environment...Only 2 reports of a loud boom occurred when the condenser coils had to be cleaned..

Liquid tite is useless when it’s not in the connectors. Seen lots of condensate in the liquid tite also, With water pouring out...gee! Any wonder why wires get corroded? Seen the same in weatherproof boxes also! I drill a small hole of the Lower bottom Corner so no more condensation problem in the boxes...It’s very annoying to see..

On BX And AC I counter twist the shielding to open it and used my diagonal snips to cut it. The Wire is not harmed that way..A few other techs have now copied my technique..

[Scoobie]

Scoobie's posting does explain why everything should be bonded to the system's grounding electrode conductor. Without each AH, AC, or furnace properly grounded/bonded that shock could have come from various places. Even a bare "hot" wire touching the ductwork could have sent that stray current out to the AC thru the AH/furnace via the ACR lines.
So you could have gotten "zapped" at any of these other points. But if each item is grounded/bonded then a CB somewhere would trip if the fault current was high enough.


I think that "BX" is a trade name for AC cable. The outer metal jacket of AC cable is supposed to qualify as a ground conductor if installed correctly. It has/had a 16 gauge bare aluminum wire that is supposed to be folded back under the cable connector insuring continuity of the ground path.......this has to me always seemed flakey and no one has really come up with a true explanation....some say you do not have to fold back and bond the 16 gauge AL etc......I do not trust any flex connector to provide proper grounding (IMO)

MC has a green grounding conductor. The outer sheath of MC is not considered a proper grounding path. MC cable is much easier to strip/work with, a sharp knife could score the sheath and then a quick bend would snap the AL sheath and you slide it off.

AC cable may have a green grounding conductor and the outer sheath is considered a redundant ground path and IIRC AC cable, with ground, may be used in medical patient care areas that require redundant grounding.

The early AC was some miserable shet to work with, it had bad insulation that after some years would just fall off.....easy to nick when removing sheath even with the proper cutter.
I would replace it when possible.

MC is impressive looking but still has the same protection requirements of Romex.
For instance if below 6 1/2' above the floor it must be drilled thru studs or mounted on a guard board... Flexible metal conduit (even aluminum) requires less protection even though it looks about like MC.

I have remodeled several jobs where the 1/2" EMT was the grounding means.
I had a collection of pictures and burned fittings/locknuts that failed as a grounding means. Some EMT connectors are weak physically and if broken from bad install and supports will lose the ground path.
For probably the last 30 years I have run a green ground wire in all raceways, even though not required. Every box along this path is grounded with the green screw.

There are "forensic analysis" articles in magazines....there are lawyers everywhere, they will hire electrical pros to analyze for any liability.

Over 40 years I have read the code Q&A's in ECM and EC magazines. It is amazing of the disputes with an inspector about needing a ground wire in that less than 6' of flex.
For the time spent with the argument and possible reinspection fees it seems like the best thing would be to include the ground wire......it is something of a scrap length of copper....you could strip the conductor if you do not have the green wire....(I have done that....sometimes just the ends that are visible....but let's not go there).

I started wiring houses for a contractor in 1969, we had to drag in 2 boxes of each type of romex. Only the outlets got cable with a ground wire....it was just a cheesy # 16 copper.
All the switching and light got cable without ground wire.
The EC was cutting cost to the bone...but everything was inspected and up to code.

Just to show you how things have changed in a short?? few years....God now I feel old!

I remember when I first started working in the biz in the duct fab shop, a long time ago. We had to put copper strips across the canvas connectors we made. I had no idea why we did that at the time...

[TechmanTerry]

Geez, I thought the aluminum wire inside the BX was for a production line purpose and was NEVER intended to be a safety ground.

Geez, I thought that the MC cable had THHN wire in it,and a dedicated ground wire, and the THHN made MC cable suitable for connection up to fluorescent light fixtures, and that "special MC connectors "are required. And a BX connector IS NOT a MC connector.

[stumpdigger]

EMT and Ridgid conduit can be used as the equipment ground conductor according to code as long as installed correctly.

But, personally, I’d run a wire as an added measure of safety... ...what happens if a conduit connection happens to pull apart, thereby losing the path back for fault protection?


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Excellent point! I can't count how many dungeons I've been in with conduits hanging down and only the wire holding it together. (probably with the emt that wasn't reemed/ deburred.)

[Scoobie]

I’d say very few “incidents” from conduit intended to be the ground failing. Prolly more likely to be struck by lightening than sloppy conduit that fails to ground. Hacks not grounding stuff, or antique installs with no grounds are the stinkers.

[kangaroogod]

Since only highly trained professionals install emt and of course permits are always pulled with thorough inspections, what could go wrong?

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