Noalox on copper to copper connections
Noalox on copper to copper connections
(OP)
We've had trouble with overheating on connections to an 85A contactor. Not sure if lug was improperly tighteded at installation or it just loosened from thermal cycling, or we may be pushing the IEC contactor too far, overheating the contact that then overheated the wire. Burned off the wire & destroyed the contactor.
I know Noalox must be used on any aluminum connection. Can it be used on a copper-copper connection to improve the conductivity? Are there any compounds formulated for copper connections?
Thanks
I know Noalox must be used on any aluminum connection. Can it be used on a copper-copper connection to improve the conductivity? Are there any compounds formulated for copper connections?
Thanks





RE: Noalox on copper to copper connections
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Noalox on copper to copper connections
RE: Noalox on copper to copper connections
Another thought: is this on the input of the rectifier, or the output? AC-rated contactors on DC duty tend to have a short and tortured life, especially switching a highly inductive load such as a generator field winding. If this is the case then consider one of the bar & shaft contactors for severe DC switching. ABB's R-Line is one of the more reasonably priced ranges, although none are 'cheap'.
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If we learn from our mistakes I'm getting a great education!
RE: Noalox on copper to copper connections
5 will get you 10 that you used DLO or "Welding Cable" or some other sort of extra flexible finely stranded conductor and the standard termination clamps that came with the contactor.
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RE: Noalox on copper to copper connections
Ambient may be part of the problem, but there are 3 4" fans blowing air through the enclosure. However, the external ambient can be quite warm too. I'll put a sensor in one of the units, (there are 10 of them), check it out.
Connections were made with THHN, not motor lead wire. Contactor includes its own clamping terminals.
Contactor is on input to the power supply. Power supply has a quenching diode to absorbe reverse transients.
RE: Noalox on copper to copper connections
Experience and workman-ship may be more important than many realize. An experienced electrician will flex or roll the cable as it is being tightened. If the conductor is entered and the lug tightened on it with-out using a rolling motion, a slight twist will cause the cable strands to untwist and become loose.
I have asked green electricians to tighten a set screw lug as tight as they were physically able on 7 strand #2 AWG cable (Possibly the worst size and stranding.) Then I give the cable a slight twist and it will come loose, often dropping out of the lug by gravity. I have cleaned up the damage from a lot of loose connections over the years. At 85 Amps you are in the sweet spot for possible workmanship issues.
Bill
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"Why not the best?"
Jimmy Carter
RE: Noalox on copper to copper connections
I would just like to ask about the joint that failed? when the lug was tightened was it to a torque and was any lubricant used?
The reason I ask is if the joint was made dry and you now use Noalox, it may cause the joint to be over tightened if the Noalox comes into contact with the bolt threads as it will reduce the friction factor for the same given torque, should this occur the joint might well fail again in the near future.
desertfox
RE: Noalox on copper to copper connections
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Noalox on copper to copper connections
RE: Noalox on copper to copper connections
By the way, I have compared notes with Utility electricians, and they often do not use NOOX, they have their own exclusive yellow "stuff" which looks a lot like vaseline....????
What is it? Is it better than NOOX?
RE: Noalox on copper to copper connections
BTW Skoggs, Seven strand cable is the worst. Flexible cable with a large number of fine strands is not as susceptible. You may not have an issue with European cable strandings. But if you are working on a machine in NEMA land be aware. Older cables are more likely to have fewer strands and be more problematic.
Bill
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"Why not the best?"
Jimmy Carter
RE: Noalox on copper to copper connections
RE: Noalox on copper to copper connections
Bart
RE: Noalox on copper to copper connections
RE: Noalox on copper to copper connections
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Noalox on copper to copper connections
I see that. Conductive without metal? Wonder how they do that.
Anyway, Noalux (not NOOX)on copper would put zinc in the joint causing a higher resistance than an untreated connection.
RE: Noalox on copper to copper connections
Because often that is available.
From the Penetrox description:
If it's Penetrox or nothing I'll use Penetrox every time.
Bill
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"Why not the best?"
Jimmy Carter
RE: Noalox on copper to copper connections
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If we learn from our mistakes I'm getting a great education!
RE: Noalox on copper to copper connections
Note the plural "compounds". They are refereing to the line of products, not a single formulation. Penetrox E is the formulation recommended by the manufacturer for this type of connection. See page 74 of http://eca
The other formulations are for aluminum to aluminum or aluminum to copper.