Difference in Duplex Receptacles

brad225

brad225

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My EE friend Phil was over this morning to take some electrical measurements on my speakers for some speaker cables he wants to build and have me try.

He took some other measurements of things out of curiosity. He was very surprised when we checked the voltage leakage between neutral and ground of some receptacles in my room.

My amps are plugged into 20 amp Shunyata duplex receptacles compared to a the 20 amp Leviton receptacles that my speakers and subs are plugged into.

The leakage on the Shunyata was 1.1 milli-volts. The leakage on the Leviton was 800 milli-volts.

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.

I will be changing the Leviton outlets better quality outlets.
 
It's not leakage voltage! This is normal and correct, it's not about the receptacles, it's about the circuit.
In any circuit that is using power, there will be a voltage between the Neutral and the Safety Ground. The more current in the circuit the more voltage, difference, that's how electricity works. I use a room space heater for this kind of test. Might see 2V or more with the heater on and near 0V with no load on a circuit. If the N & SG difference in near 0V with load, you have a dangerous Bootleg Ground.
Those little 3 LED testers are not smart enough to find this dangerous problem.
 
This is not a Bootleg Ground issue. Each duplex is on a separate breaker. There is #10 Romex run from each outlet to the main panel 25' away. No wires crossover anywhere that would cause this. This is an issue in the design of the outlet.

The orange outlets you see people using that are generally used in hospitals as they offer an extra grounding protection between the neutral and ground.

This was done with no load on any of the outlets. How would you possibly get a numerical reading from a 3 bulb LED tester you appear to suggest was used?
 
Sorry about the 3 LED tester part, that was an after thought for other readers.
There is no way any receptacle in good repair can have leakage currents like that.
Maybe it's the problem that Bill Whitlock wrote about:

"Ground Loops: The Rest of the Story"
Bill Whitlock, AES Fellow and Jamie Fox, P.E.
http://www.jensen-transformers.com/...est-of-Story-Whitlock-Fox-Generic-Version.pdf

skip over the math pages.
 
I agree that there is something wrong with the Leviton receptacles. That is why I am changing them out.

I without a doubt believe it is a case of cheap, non standard products that Home Depot, Lowes and other large purchasers sell.

It is not an isolated item as all of the Leviton receptacles in the room and they are all on separate breakers in the panel.

I believe Shunyata starts with Hubble products for their receptacles so I might try one to see how it tests first.
 
I'm not a fan of Leviton receptacles either.
But lets look at the circuit differently.
With a 20 foot 10 AWG Romex® run, there is about 0.1 Ohm resistance between the receptacle Neutral & Safety Ground pins.
Using Ohm's Law: I = E/R or 0.8V/0.1R = 8 Amps of current.
 
Thinking further:


  • Do the 2 Romex's® return to the main breaker box or a sub-panel?
  • Do the 2 Neutral wires connect to the same Neutral bus bar?
  • Do the 2 Safety Ground wires connect to the same ground bus bar?
 
Last edited:
Something’s amiss here apart from the outlets. Pull the outlets out altogether and measure the voltages at the bare wire ends. Be careful. Report back.
 
Speedskater said:
Thinking further:


  • Do the 2 Romex's® return to the main breaker box or a sub-panel?
  • Do the 2 Neutral wires connect to the same Neutral bus bar?
  • Do the 2 Safety Ground wires connect to the same ground bus bar?
Click to expand...

All 8 circuits from the listening roo runs to the same main breaker box that is 25' away.

It is a Square D QO panel that is 8 years old. The entire run from the pole underground to the meter housing and disconnect is 8 years old. This includes our own green transformer box that is on a concrete pad and 300' from the house.
The panel is within 3' of the meter housing/disconnect on the inside of the house wall.

It really seems the Leviton product is not a quality one.
 
W9TR said:
Something’s amiss here apart from the outlets. Pull the outlets out altogether and measure the voltages at the bare wire ends. Be careful. Report back.
Click to expand...

I will do that but, all of the outlets in the room showed the same proper voltage.

The 3 Shunyata SR-Z1 outlets had the 1.1 milli-volt reading and all the Leviton had readings in the range of the 800 milli-volt between neutral and ground.
 
I’m not suggesting that the Leviton outlets are good - they are probably garbage. But this just doesn't make sense to me.

Do you have a torque wrench and have you checked the torque on all the connections? The Square D website will have torque specs for all the breakers and buss bars. Ensure that everything is torqued to spec.
 
W9TR said:
I’m not suggesting that the Leviton outlets are good - they are probably garbage. But this just doesn't make sense to me.

Do you have a torque wrench and have you checked the torque on all the connections? The Square D website will have torque specs for all the breakers and buss bars. Ensure that everything is torqued to spec.
Click to expand...

Hey Tom, I was not aware of Torque settings? I will look into this myself for the heck of it.


Sent from my iPhone using Tapatalk Pro
 
Speedskater said:
Be very, very careful when doing tests like these. While Tom & I are experienced working with dangerous electricity, if you make a mistake, you don't get a do-over.
Click to expand...

Yeah, I can see a bunch of audiophiles buying torque wrenches to torque down electrical connections they know nothing about. What could possibly go wrong?
 
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.
 
Speedskater said:
Be very, very careful when doing tests like these. While Tom & I are experienced working with dangerous electricity, if you make a mistake, you don't get a do-over.
Click to expand...

Yes, you are correct, I just never heard of torque wrenching at the panel aside from most electricians understanding how sound can be improved with power in our world.


Sent from my iPhone using Tapatalk Pro
 
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.
Click to expand...

Thanks Tom,

Totally clear, and makes sense.


Sent from my iPhone using Tapatalk Pro
 
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.
Click to expand...

I find it risky that you are promoting audiophiles with no electrical experience to buy torque wrenches to tighten down connections inside of their power panels when the electricians that wired the house and the panel didn't use a torque wrench. If it is so vitally important to torque all of the connections, why aren't electricians doing it? Probably because they follow the old rule that tight is tight and too tight is broke. So, if you want audiophiles to jump down the torque wrench rabbit hole, lets talk about calibration. Does the torque wrench come with a certificate of calibration? If so, how long is it good for? Once the calibration date expires, what's the plan and periodicity for keeping the torque wrench in calibration? How much will the calibration cost? Will it be cheaper to throw out your $30 torque wrench that probably never came with a certificate of calibration in the first place and just buy another one? You really don't want to use a torque wrench that's out of calibration to make these oh so critical connections do you?
 
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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