More than one wire under a screw terminal

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Jraef

Moderator, OTD
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Electrical Engineer
As to the two conductors in the green/yellow (PE) terminals, there is some widespread confusion on that issue. There are some manufacturers out there that, under IEC rules, say that you can have up to 3 conductors, so long as the total cross sectional area doesn't exceed the design of the terminal. So people read that and think it's OK.

But here, the use and listing of the blocks falls under UL and ALL of these IEC style DIN rail terminals are only UR (Recognized Component), meaning they can ONLY be used in assemblies that themselves will be UL listed. In that process, UL will NOT allow more than one wire per terminal, unless, in sync with the NEC, it is explicitly LISTED for that, and the UL file for IEC DIN rail terminals doesn't allow that. So despite the fact that the TB mfr may say it's OK under IEC rules, that becomes irrelevant here. I used to work for a company that sold and used IEC terminal blocks, this was a constant source of pain and confusion.
 

jap

Senior Member
Occupation
Electrician
I just noticed I've been spelling DIN rail with an e instead of an i

My bad. :)


JAP>
 

kwired

Electron manager
Location
NE Nebraska
I just noticed I've been spelling DIN rail with an e instead of an i

My bad. :)


JAP>
I was tempted to poke fun at you on how particular you said you were when making up such things yet you can't even spell some of the components correctly;)
 

jap

Senior Member
Occupation
Electrician
I was tempted to poke fun at you on how particular you said you were when making up such things yet you can't even spell some of the components correctly;)

I'm glad you didn't.
I know you're in the farming community,, I'd come charging at you with a bindicator if you did that. :)


JAP>
 

kwired

Electron manager
Location
NE Nebraska
I'm glad you didn't.
I know you're in the farming community,, I'd come charging at you with a bindicator if you did that. :)


JAP>

Wonder how many that participate here know what a bindicator is? I'm talking original product that has bindicator as a trademarked name, there may be other items that get called that at times, as well as other items from same company that have that name associated with them.
 

jap

Senior Member
Occupation
Electrician
Wonder how many that participate here know what a bindicator is? I'm talking original product that has bindicator as a trademarked name, there may be other items that get called that at times, as well as other items from same company that have that name associated with them.

Doesn't matter as long as you know what it is. No one else called me out on my bad grammer.
I guess I could blame it on the auto correct thing.

And yes I did mean the roto type. :p

JAP>
 

retirede

Senior Member
Location
Illinois
This IS what came from the factory. Besides, Oil drilling facilities are BEYOND cheep. Considering a drill site has a life of less than 30 years, they don't care. But who knows, Technology keeps improving. Rod Pumps, Gas Lift, Submersible pump, Fracking

May I ask what kind of equipment this is and the name of the manufacturer?

Just curious as I used to work for a manufacturer of drilling equipment.
 

jap

Senior Member
Occupation
Electrician
Seems you do know what they are then.

Do you know what a "Stirrator" is or a "Shivvers" system? Both those becoming things of the past, how about more modern "power sweep"?

Do not.
My 1st day on the job in my electrical career was on top of a grain bin installing a bindicactor with the motorized paddle. Then onto the limit switches for the indicator lights in the distributor head on a 130' grain elevator then to the vibrators to rattle the stuck feed out then to the pulse socks on the dust collector then to the controls for the cyclone blender then to the shaker for the fines and overs then to the size 5 soft start for the pellet mill then to the controls and interlocks for the auger under the mixer then to the load out auger under the scale then to the mollasus blender then to the air compressor controls then to the size 4 starter for the hammer mill then to the to the ....... oh well you get my point. :)

Jap>
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
My 1st day on the job in my electrical career was on top of a grain bin installing a bindicactor with the motorized paddle. Then onto the limit switches for the indicator lights in the distributor head on a 130' grain elevator then to the vibrators to rattle the stuck feed out then to the pulse socks on the dust collector then to the controls for the cyclone blender then to the shaker for the fines and overs then to the size 5 soft start for the pellet mill then to the controls and interlocks for the auger under the mixer then to the load out auger under the scale then to the mollasus blender then to the air compressor controls then to the size 4 starter for the hammer mill then to the to the ....... oh well you get my point. :)
My vote for the longest unbroken sentence on the forum. :p
 

wireman

Inactive, Email Never Verified
Many terminals are rated for more than one wire. Sometimes it just takes a little digging to find the right document.
 

jap

Senior Member
Occupation
Electrician
Many terminals are rated for more than one wire. Sometimes it just takes a little digging to find the right document.

And generally best if that document is found before the terminal is installed and terminated.


JAP>
 

motormuff

Member
I believe this is MC cable

I believe this is MC cable

Not familiar with the cable in question, but something tells me the three together must be used as one EGC - so that sort of makes it one conductor? Kind of like the concentric bare conductor in SE cable or other similar cables.

They appear to be smaller then the insulated conductors on what looks to be less then 10 AWG, but not really certain what thickness of insulation is either.

Some types of MC cable utilize the metal jacket plus the undersized copper conductors to make up the EGC. If I was doing it just to be sure I would use a grounding bushing on the cable connectors and include that as part of my ground path. If the cable would ever short to the metal jacket there may not be a low impedance path to trip the over current device, which could allow the metal jacket to remain energized. Could be lethal if some one were to touch the cable and come in contact with the jacket. On some types of MC cable those undersized ground wires may be spot welded to the metal jacket. Follow the manufactures recommended instructions.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Seems you do know what they are then.

Do you know what a "Stirrator" is or a "Shivvers" system? Both those becoming things of the past, how about more modern "power sweep"?
I know what a Bindicator is, but not the others. Bindicators are used a lot on the aggregate industry too.

Speaking of old terminologies, I was doing a talk on circuit testing the other day for a bunch of irrigation district electricians and mentioned a "Wiggy". I got a lot of blank stares. Even when I explained what it was, still nothing.
:slaphead:
 

kwired

Electron manager
Location
NE Nebraska
Some types of MC cable utilize the metal jacket plus the undersized copper conductors to make up the EGC. If I was doing it just to be sure I would use a grounding bushing on the cable connectors and include that as part of my ground path. If the cable would ever short to the metal jacket there may not be a low impedance path to trip the over current device, which could allow the metal jacket to remain energized. Could be lethal if some one were to touch the cable and come in contact with the jacket. On some types of MC cable those undersized ground wires may be spot welded to the metal jacket. Follow the manufactures recommended instructions.

AC cables and more recently some MC cables have bare "bonding conductor" inside which it's only purpose is to be in intimate contact with sheath and provide additional bonding between coiled sections of the metallic sheath. They aren't even intended to be terminated wherever you strip the sheath for terminating cable, the sheath along with such bonding conductors is the EGC and terminating in a listed fitting is all that is necessary to complete the EGC.
 
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