Here is an issue that has been bugging me for some time. It seems like it has become a somewhat acceptible practice to install a stranded wire with a grounding screw. I don't see that as being a very safe practice. Is there anywhere in the code book that prevents this, or is it a listing issue?

Thanks,

Laura

110.14(A). By the way, the screw doesn't have to be green

I don't see anything in 110.14(A) that requires the wire to be solid, so are you saying that it's ok to use stranded wire?

Laura

p.s. I knew adding green to the grounding screw title would grab more attention

Hi Laura. In my opinion, yes it can be stranded, as long as makes a good connection, as required by 110.14(A).

A trick I learned long ago is to twist the stranded wire counter-clockwise, then when the screw is tightened, the wire doesn't spread quite as much. Of course, the best way is to solder the end of the stranded wire, then bend it into an eye, like a solid wire. Or, crimp an eye hook onto the end.

Said I was done BUT!!! here we go again.
one and two family dewellings (Electrical Systems Published by the International Association of Electrical Inspectors.Page 161. 5th Edition. Quote The Requirements for a "Grounding screw that shall be used for No other purpose "Precludes the use of a cable clamp screw for connectiong the Equipment grounding screw for connecting the equipment grounding conductor Goes on to say secured under a cable clamp Never was approved for grounding .The typical box is REQUIRED to be proved with a tapped hole engraved with the marking GRND or GR that is to be used for that purpose!!!Lets not go on now about other boxes ect the subject ist hand was boxes with clamps. I never said screw must be green Just a approved gr. screw. Read it and weep. Thats A.I.E.I. Interperation Guys.Again its in pics for your viewing pleasure.

From a legal perspective, the opinion of the IAEI and the opinion of my 4 year old daughter are one and the same.

Yoopersup, please direct me to the thread (and user name of the person) where somebody said you could use the screw in the clamp to ground a box (while still being used for the clamp). All I can find is people saying that the screw does not need to be green.

The NEC (which is what you must abide by) does not require the screw to be listed for the purpose. Standard 1/4-20, silver colored bolts are "legally" used everyday to attach ground lugs to boxes.

Are you strictly a residential electrician? If you where used to large commercial jobs with heavy gauge wire then the thought of a ground screw needing to be listed would not even cross your mind.

Ryan,
I absolutly loved that answer.
Richard

Ryan_j
I;ll be sure to pass your respect of the IAEI at the next meeting. As most inspectors are Members and there books are accepted world wide. Why do you guys keep going to large J boxes??? we are talking about standard boxes with cable clamps Gzeee !!!
By the way I;ve ran jobs from housse wireing to multi millions From coast to coast Licened in 10 states and as an instructor in 5 , How about you guys????
'

Yoopersup,

This thread is about using stranded wire with a grounding screw.

Bill

Guys its been fun but we:re really beating this to death , I;ve brought up books backing what I have to say but like they say in the old days Buy um books , buy um books but all they do is eat the covers. Been fun but really time to move on .

Yoopersup,

With all due respect, you're bringing up things from another thread that are unrelated to this one. Please go back and reread that one because it seems you are arguing a point that that no one disagrees with.

Bill

I have no disrespect for the IAEI...in fact I'm on the board of director's for my local chapter and am very active with them, I am teaching for them next month and sat on a code forum for them last week.
Also, don't look now, but you're the onewho keeps bringing the subject up.

BTW: I'm not interested in your resume, although it is very impressive.

Unless I've missed the point, those green wire grounding pigtails you can buy at the hardware store are made of #12 stranded wire. One end has a spade lug at one end, and an eyelet with a green screw at the other.

With older boxes, I've put the screw into the otherwise unused threaded hole meant for a cable clamp. The box has a clamp on the other side for the cables. I think that this is okay, yes?

In practical terms, for me, the width of the screw head skirt on a ground screw is about the same as the side wired device terminal screw head skirt. It works reasonably well on stranded and fine on solid.

Now, if I'm forced to use a standard 10-32 round head machine bolt for a ground screw, I'd argue that the skirt is so narrow that even solid wire won't reliably terminate under it.

LMAO Ryan Does that mean I should get my 4 year old's opinion on electrical issue?

Simple thing I've done when needing to put a stranded ground wire under a ground screw is strip insulation back on the wire about 8 inches, baring around an inch or so, leave the insulation on the end & twist... bend the bare part of the conductor under the screw & twist the insulated portion a little more, this tightens the strands together & makes it easier to keep all the strands under the ground screw.... Not to mention you now have a length you can attach a device or other ground wires to without adding another pigtail for the box & even if I don't need it, I leave the length in the box in case someone else comes behind me & needs to add something... Less risk of someone improperly grounding whatever they're doing

-Randy

I've had some E-mails about my comment, so let me elaborate on what I am trying to say. The only interpretation of the NEC that is a legal one comes from the CMP's of the NEC, not from any other party. Any other opinion is just that...an opinion. No different than yours or mine legally.

In no way do I mean any disrespect to the IAEI or the author(s) of their publications. As I stated before, I am a member in good standing with the IAEI and appreciate all that they have done for the industry.

"The typical box is REQUIRED to be proved with a tapped hole engraved with the marking GRND or GR that is to be used for that purpose!"

yoopersup, I looked at a few different old works today and didn't see any marking around the location typically where the ground screw would go.

I concur with Joey D. All of the Raco and Steel City 1 gang and gangable device boxes I have in stock are missing the GND marking completely. Only the Raco 232 4x4 boxes with the raised dimple with a tapped hole say GND. I checked Raco 590, 390, 601 and 605. I also checked Raco 145 octagon box with RX clamps. No GND stamp. Now what?

I have a class on tuesday taught by a local inspector and I will ask him what he thinks.

>>>The typical box is REQUIRED to be proved with a tapped hole engraved with the marking GRND or GR that is to be used for that purpose!!!Lets not go on now about other boxes ect the subject ist hand was boxes with clamps.

Like 'em or hate 'em, Appleton and others still sell UL Listed ground clips. I don't have the bible handy, but can we still use those?