New shop, electrical question

I'll post pics and specs on my new shop once I have it all setup, I am moving into a 1,500 sq ft barn and getting a few new tools.

My landlord (the farmer) added some additional electrical for me. Hehad an electrician put in a 220 circuit and run some metal conduit out to where I wanted the 220 plug and put it in a metal jbox. He also ran two wires for an aditional 110 circuit to the same jbox all inside metal conduit. I will pull the 110 out and route it to where I want the extra juice.

I do lots of home electrical and can follow the diagrams well and know some of the codes, etc. I have always used romex or armorcable. I want to come out of this steel jbox with some armor cable to a 4 gang outlet, then out to a 1/2 switched outlet and then another switched outlet. I am familar with how all that is done but have the following question (finally).

Do I attach the ground wire in the armor cable to the jbox? Once I go out of one of the switches I will use romex overhead and I want to be sure everything is grounded correctly. I guess the metal conduit and boxes are ground enough to just run the two wire 110 but when I come out to armor cable and romex I want to be sure I am grounded no?

BW Hoping I don't burn the place down or lectracute mysef. The farmer wouldn't be happy.

Reply to
SonomaProducts.com
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As far as I know you need the safety ground wire to be continuous throughout your wiring, from the fuse box to each outlet. The ground wire in each outlet box connects both to the outlet and to the box itself.

I wouldn't count on the armor to be a ground connector, it's not exactly a copper conductor. Safety first!

Anyway, if you don't get it inspected by an electrician you might get in legal trouble from the landlord if there's a problem, even in the future after you leave!

Reply to
BobF

Easy way around the latter. Cut the wire off when you leave.

Reply to
clare

BW

Armor is armor. Nothing else. The ground must be defined and in this case it is the bare or green wire with in the armor cable.

Conduit is nice and probably required since you indicate that the wiring will not be exposed. Exposed romex or the like will not cut it now.

The additional wires indicate that there is no ground wire and it will have to be added.

A subpanel with the required breakers should have been added. Also a ground rod should be provided for additional protection. Especially if the barn is constructed of combustible material.

Armor cable, conduit and boxes have no listed electrical characteristics and therefore should not be part of any required ground protection.

Bob AZ

Reply to
Bob AZ

It doesn't have to be copper.

The NEC explicitly permits the use of (among other things) the armor of type AC armored cable to be used as the equipment grounding conductor. Other acceptable grounding conductors include aluminum wire, EMT, rigid metal conduit, flexible metal conduit, and flexible metallic tubing. [2008 NEC, Article 250.118]

Reply to
Doug Miller

That is incorrect. The armor of type AC armored cable is explicitly recognized by the NEC as an acceptable equipment grounding conductor.

??? Why would conduit be required if the wiring will be concealed? [...]

Totally incorrect. In addition to cable armor, the NEC also recognizes rigid and flexible metallic conduit or tubing as acceptable grounding conductors.

Reply to
Doug Miller

In Canada armored cable is not considered a ground conductor. A continuous ground conductor must be run.

E.M.T. does not suffice a s a ground conductor and a separate grounding conductor must be run. The little screws that hold EMT together can have physical strain on them, separate and are not good grounding systems and not to Canadian safety code. EMT is not physical protection for wiring and only a method running wires. It takes conduit (rigid) to offer physical protection.

I find this hard to believe the NEC would differ that much on armored cable. Who would use a grounding conductor that is made out of who knows what crap metal and has an inductive coil made out of it? Sounds like somebody has their wires crossed.

Reply to
Josepi

Wonder why they put grounding conductors in armored cables. I doubt people would pay for the extra conductor if they could use the armor for a ground in either country.

Doug misinforms again.

In Canada

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USA

E.M.T. does not suffice a s a ground conductor and a separate grounding conductor must be run. The little screws that hold EMT together can have physical strain on them, separate and are not good grounding systems and not to Canadian safety code. EMT is not physical protection for wiring and only a method running wires. It takes conduit (rigid) to offer physical protection.

I find this hard to believe the NEC would differ that much on armored cable. Who would use a grounding conductor that is made out of who knows what crap metal and has an inductive coil made out of it? Sounds like somebody has their wires crossed.

Reply to
Josepi

Actually EMT IS adequate protection under Canadian code for exposed wiring in a lot of areas. (like basement walls and residential garages)

Not that many years ago "BX" armoured cable was accepted as a safety ground in Canada too - and the current "MC" cable, with aluminum shield and a separate bonding ribbon also passes.

Reply to
clare

Doug

Typo on the "Not be exposed". Should read "wiring will not be exposed".

I will have to reread the paragraph you mention. On a big electrical job I kept up with 2 years ago this was an inspection item. No conduits, flexible or not was acceptable as a ground conductor. Yes the conduit was grounded and the boxes also but with a specified ground conductor.

Reply to
Bob AZ

That *is* what it reads; that's why the statement makes no sense. Did you mean it should read "wiring will be exposed"?

Perhaps there's a local ordinance prohibiting it, or perhaps the inspector doesn't understand the Code, or perhaps that was specified by contract. But it's not prohibited by the NEC. The NEC doesn't permit a total of more than 6 feet of flex in a ground-fault path, but there is no such limitation on rigid or intermediate, or on EMT.

Reply to
Doug Miller

formatting link
this is 2002 NEC it is pretty handy advice that covers a lot of issues, and the links are useful also.

Reply to
Swingman

Yeah, I remember running into all kinds of old crap back in "the old days". The code violations were brutal and I wonder how some of us survived...LOL

BX cable should have had a grounding strip /ribbon run inside the steel armour. Steel (in a helical coil) is not considered a good grounding conductor and if the ribbon existed it had to be used.

From the Ontario Hydro Electrical Safety Code - 19th Edition - 1983

Rule 10-510 Fixed Equipment (2) The armour of those constructions of armoured cables incorporating a grounding conductor shall not be considered as fulfilling the requirements of a grounding conductor for the purposes of this Rule, and the grounding conductor provided in these cables shall shall comply with Subrule (1)(b).

**(states the conductor shall be bare or green)

(3) The armour of flexible conduit and liquid-tight flexible metal conduit shall not be considered as fulfilling the requirements of a grounding conductor for the purposes of this rule, and a separate grounding conductor shall be run within the conduit.

EMT was never considered mechanical protection but could always be used in places where romex was Ok just strapped to a wall to keep it neat.

1983 rule. Sorry I was too lazy to find it in the new code book

Rule 12-1502 Use (EMT) Electrical metallic tubing may be be used for exposed and concealed work except that it shall not be used: (a) Where it is subject to mechanical injury either during installation or afterwards; (b) in any hazardous location; etc... corrosive, wet, concrete, earth contact, corrosive vapors...

Actually EMT IS adequate protection under Canadian code for exposed wiring in a lot of areas. (like basement walls and residential garages)

----------------- On Wed, 7 Sep 2011 23:19:56 -0400, "Josepi" wrote: In Canada armored cable is not considered a ground conductor. A continuous ground conductor must be run.

E.M.T. does not suffice a s a ground conductor and a separate grounding conductor must be run. The little screws that hold EMT together can have physical strain on them, separate and are not good grounding systems and not to Canadian safety code. EMT is not physical protection for wiring and only a method running wires. It takes conduit (rigid) to offer physical protection.

I find this hard to believe the NEC would differ that much on armored cable. Who would use a grounding conductor that is made out of who knows what crap metal and has an inductive coil made out of it? Sounds like somebody has their wires crossed.

Reply to
Josepi

Ya, the code is one thing... safety is another. I've seen armored cable where the armor was no longer connected to the box, just hanging in the air, or barely attached by rusty screws. In that case a short to ground could blow out the rusty connection and leave the ground hot.

In some types of installations, such as computer systems or recording studios, dedicated ground wires are ran to eliminate electrical noise. The equipment chassis ground is connected to the safety ground wire but not the armor. Sometimes these outlets are colored orange.

Reply to
BobF

Poor workmanship is poor workmanship - whether metalic sheathed cable or Romex. ANd to meet code, the RIGHT box connectors are required. In Canad, the galvanized BX (obsolete now) does NOT meet code. And the AntiShort is absolutely necessary.

Virtually ALL isolated ground receptacles are orange - and they all have a green triangle on them. The "U" ground is not connected to the mounting bracket (hense the "isolated ground" - and the bare safety ground connects to the box - which also grounds the cover plate if it is metal - while the ground terminal (green wire by code - sometimes red wire of NMD3 cable, taped green at both ends) runs DIRECTLY back to the ground buss on the panel. This pretty well limits a "isolated ground" circuit to ONE duplex receptacle - or possibly 2 isolated ground reeptacles in one box.

Reply to
clare

Don't blame the armored cable for that. Blame an incompetent installer.

Probably not before tripping the breaker...

Reply to
Doug Miller

"Look at me" syndrome or just losing it? Read what he stated again and stop trying to disagree regardless of what people post.

Is this another case where the hot wire can feed current into a box and it doesn't return to the source "vapour currents" but, it can still trip the breaker?

Perhaps this is another one of your imaginary current circuits, like the bathroom fan circuit, where the current fills up the device before it continues to the rest of the circuit?

Don't blame the armored cable for that. Blame an incompetent installer.

Probably not before tripping the breaker...

Reply to
Josepi

The conduit and metal boxes constitute the Mechanical Grounding. The bare copper conductor (or green wire) constitutes the Electrical Ground. So, all your conduit should be mechanically "bonded" one to the other and all your devices should be connected to the Electrical Ground at the source.

Note: You can never have enough electrical outlets.

For lighting, I use (switched - 4-wa, in my case) grounded outlets in/ on the ceiling to accept the plugs of those cheap fluorescent "shoplights" I get at HD or Lowes ($8-10) as it makes changing our ballasts/fixtures a snap (well, a de-hook/re-hook)

Reply to
Hoosierpopi

That is incorrect.

The term "mechanical grounding" doesn't make any sense, and is not a concept recognized by the NEC.

Moreover, the NEC makes no distinction between rigid metal conduit, intermediate metal conduit, electrical metallic tubing (aka EMT or thinwall), copper wire, or aluminum wire, in terms of their suitability as equipment grounding conductors: all are equally acceptable.

Reply to
Doug Miller

I bet the NEC makes no distinction with glass and plastic for grounding either. This doesn't make it OK as there are other rules that you don't seem to be able to see with your HUHAS.

The term "mechanical grounding" doesn't make any sense, and is not a concept recognized by the NEC.

Moreover, the NEC makes no distinction between rigid metal conduit, intermediate metal conduit, electrical metallic tubing (aka EMT or thinwall), copper wire, or aluminum wire, in terms of their suitability as equipment grounding conductors: all are equally acceptable.

------------------- On 9/9/2011 11:58 AM, Hoosierpopi wrote: The conduit and metal boxes constitute the Mechanical Grounding. The bare copper conductor (or green wire) constitutes the Electrical Ground.

Reply to
Josepi

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