Difference in Duplex Receptacles

As to tightening torque for connectors and terminals. NEC Article 110.14(D) is about torque, some products have a recommended value or range while others have a proscribed value or range. But I would guess with most residential electricians, if you hide their torque wrench they might not notice it for a month.
 
I am promoting the fact that proper torque is foundational to all electrical panel installations.
If you are not comfortable working around 120/240 panels hire an electrician.
If your electrician does not use a torque wrench find one that does.
And yes, my torque wrench came with a C of C.
And no, it doesn't indicate a cal interval, and no I don't have a NIST calibrated torque motor to test it with.
But I do check my torque wrenches against each other and they don't drift.
 
Kingrex said:
I torque my mains and meter sockets. We torque and draw a line across every torqued lug on commercial jobs.

I dont torque my small circuit breakers any more. I have landed enough branch circuits to know what is correct. But hey, I have landed thousands of breakers. And, I have stripped out the threads not using a torque wrench.
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You've got the advantage of probably tens of thousands of connections - and lots of experience to know what is correct. The average homeowner or audiophile just doesn't.
 
I would say both camps of thought are correct here.

I use Hubbell HBL5362 for affordably priced audiophile receptacles. I just tried putting my Fluke True RMS meter across the grounds, neutral and hots on a leviton receptacle. There is no leakage as far as resistance. I still don't doubt there could be micro voltage across the neutral and ground via a receptacle. The insulating material between 2 electrically conductive materials is all that keeps them from shorting out. different materials insulate better than others. It is not at all inconceivable that a small amount of current could pass between the prongs of a receptacle. This could even be due to dirt, oil etc on the surfaces of the receptacle. I do not have a megger to induce high voltage and measure that leakage.


The basic foundation of electricity is that putting to wires in close proximity to each other will cause one wire to induce current and voltage onto the other wire. That is the reason transformers work. In its most basic form, a transformer is 2 sets of independent wires in close proximity to each other. The voltage and current from one is induced to the other. Any time you take any amount of wire and run it from point A to point B, some amount of voltage and current is inducing from one wire to the others. This can easily be measured.

I also find voltage potential issues in the main panel and sub panels themselves. For example. Square D QO is a great sub panel. Copper Bus with robust connections. However, if 2 ground bars are installed. One on one side of the panel and the other on the opposite, and a piece of #4 copper conductor is not laced between the 2 ground bars, the only path for ground between the two is through 1 or 2 small screws and the sheet metal can. There will be voltage potential difference between the 2 grounds and especially between the ground and neutral connection.

This thinking is brought back to the main panel where the subpanel is fed from. Most residential main panels have aluminum bus bars. The neutral on either side of the bus are connected with a steel jumper. There is micro voltage potential right there between the two neutral bar. Same for the ground. That whole system needs to be laced together, sometimes at multiple points to rid micro voltage differences. Where you decide to tap you subpanel feeds is critical in the main panel. You may be adding a half to almost a whole volt of electrical potential to the subfeed run right there in the main panel if you tap at the wrong place. It only compounds and gets worse the further down the line you go.
 
Speedskater said:
As to tightening torque for connectors and terminals. NEC Article 110.14(D) is about torque, some products have a recommended value or range while others have a proscribed value or range. But I would guess with most residential electricians, if you hide their torque wrench they might not notice it for a month.
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I also wouldn’t be surprised that audiophiles that suddenly become concerned with torquing the connections inside their power panels that call up electricians and ask if they will come to their house and check the torque of the connections in their power panel get hung up on.
 
W9TR said:
You've got the advantage of probably tens of thousands of connections - and lots of experience to know what is correct. The average homeowner or audiophile just doesn't.
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Just a couple weeks ago I was training one of my "Journeymen" on how to feel the torque. What he really needed to learn was how to properly handle a socket and wrench. There is a way to hold the wrench and feel the resistance. One hand wont do it. You have to use 2. You also have to "massage" copper conductors as they are torqued to get them to spread even and accept the lug. Little 20 amp CB don't need all the massaging, but you do need to have one way you always hold your square drive to know the pressure you are applying is the same every time. You also need to torque a few with a wrench, then feel them with a square drive to know what is what.

I still grab a torque wrench every time I work on the lower unit on my Yamaha outboard. I don't trust myself enough to not strip one of those bolts in an aluminum case.
 
W9TR said:
Hey Ed - every breaker panel and the associated breakers will have a torque spec associated with every connection. It’s safe and easy to check all the branch circuits - just pull the main breaker and torque away.

The main high current connections into the distribution panel - that’s a different story. I recommend getting an electrician in to that because of the arc/flash hazard. Alternately you can pull the meter.

I find it funny that people will spend $3,000 on a power cord or $300 on a fancy outlet but don’t check the connections in their power distribution panel, which takes 10 Minutes and costs $30 for a torque wrench if you don’t already own one.
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I agree Tom. When we discovered the difference I went down and re-tightened the neutral, load and ground wire for each receptacle.
Phil suggested we tighten the main lugs but i didn't have a large enough allen wrench at home. I will bring one home from the shop this week.

I have been in construction for many years and have not seen an electrician use a torque wrench since the early 80's. Thanks for bringing this up.

Fortunately, I can shut off the power for the panel at the meter housing disconnect for that panel before tightening the lugs.

Thanks for all of the response.
 
I was reading through the Jensen link from Speedskater. Joe Pitman a long time ago told me to twist the hot and neutral and leave the ground strait. I have been doing this in my made cables and pipe runs for a while now. I wish they had measured values of the LN twist in PVC and steel conduit. The loose wire in conduit is not strong on the graph, but it was not measured. It was calculated.
 
I went down to the main panel and re-tightened all neutral, ground and hot leads to all of the outlets. Nothing changed but we eliminated the possibility of a loose connection causing it.
 
My EE friend Phil is out of range for input this holiday weekend so I'll start here.

I decided to change a couple of QO breakers in by panel for the audio room to get rid of Arc Fault breakers. When I looked at the chart I made for my music room I discovered the outlets that we tested and showed leakage between neutral and ground were on Arc Fault breakers.

Can you electrical experts fill me in on how the AF breakers might cause this since they are connected to the hot buss bar and the neutral also?
 
Lisa, what were you trying to fix.

Brad, no idea. My guess is the intelligent current sensing technology may use a doughnut type current transformer wrapped around the hot, neutral and ground. Did you notice any sonic difference changing to a non intelligent breaker.
 
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