Thread: The Damage Arcing can do to a Plug and Socket

Originally Posted by cba_melbourne

I like to unplug the power cord personally and leave it on the floor where I can see it. I will not trust wall mounted switches, as some electrician may have wired them improperly. Nor will I trust a contactor in a distant fuse box being turned off, as some idiot may tun it on again anytime without me noticing.

you are supposed to LOCK it all out,. so that no one but yourself can turn it back on

Originally Posted by Oldneweng

I thought some might be interested in seeing this picture.

Attachment 344934

Caused by not having the plug locked into the socket properly (or at all), although the operator(s) said it was. The machine it was connected to was undamaged. At least one of the guys does not do up the plug locking ring at all. Been caught a couple of times when taking over a job from him and having to call the sparky for another matter.

Dean

Hi Dean,

An excellent picture of the black art of electrical connections! Out of curiosity do you recall if there was any obvious heat damage around the tunnel connectors or wiring in the back of the socket? I'm asking because the wires in the photo, close to the socket, show no blackening of the insulation. I have seen plenty of hot joints, perhaps 2 or 3 a month for more than 15 years, although not plugs and sockets. I would have thought if there was a poor connection between the pins and their sockets the heat generated would have travelled back through the socket and damaged the wiring. Perhaps the plastic starts to decompose before that happens?

Cheers

The Beryl Bloke

I must admit I am lax on doing up the lock ring on my 3ph gear.
I can assure you that has just changed !!!
You have also just pushed me to replace a damaged plug on one of my welders also, it should have been done years ago

Matt

I terminate, 3 phase 32 Amp plugs and outlets on a regular basis, On leads we use multi stranded flex and always use ferrules under our terminations in the plug and outlet. Of course it is a must to lock the ring as It can over time be pulled out slowly without knowing. The new Clipsal plugs which I like, have no cable clamp like the old ones. It relies on tightening the cable gland where the cable comes into the plug. Like has been mentioned its a must to make sure the screws are tight on the ferrules.

Wow - This is a timely post, I had a sparky round yesterday to wire in a 3 phase socket for my compressor - It has a 4 pin Clipsal plug.

Mental note to self - Screw in the lock-ring!

Thanks for posting.

Jon

Originally Posted by Theberylbloke

Hi Dean,An excellent picture of the black art of electrical connections! Out of curiosity do you recall if there was any obvious heat damage around the tunnel connectors or wiring in the back of the socket? I'm asking because the wires in the photo, close to the socket, show no blackening of the insulation. I have seen plenty of hot joints, perhaps 2 or 3 a month for more than 15 years, although not plugs and sockets. I would have thought if there was a poor connection between the pins and their sockets the heat generated would have travelled back through the socket and damaged the wiring. Perhaps the plastic starts to decompose before that happens?CheersThe Beryl Bloke

The wires as seen in the photo are not badly damaged. The insulation is melted for a couple of cm but the rest is only a bit blackened. The parts in the picture are all I have seen tho so I could not comment on the state of the other bits. Their absence infers that they were not damaged tho. Dean

I have just had look to find the scene of the crime. Took about 20secs. That brand new orange gear stands out pretty well. Hasn't been covered in red stuff yet lol. Original back section of housing, (4 unit module) has not been moved. Nor has the conduit feeding in the power. Also brand new plug on screen sitting nearby. Dean

Hi Guys,

Here in the UK the use of ferrules or hollow pins are mandatory on flexible cables. In any event it would be considered "good practice" to use them.

A mate who worked at the steel mill on their rather large currents - and more often than not, live - is a firm believer in not using pins/ferrules, with their other introduced failure modes. Find half the time I won't do up a lock-ring is because of old clipsal receptacles and cheap chinese plugs which never seem to go together cleanly.

Originally Posted by Hunch

A mate who worked at the steel mill on their rather large currents - and more often than not, live - is a firm believer in not using pins/ferrules, with their other introduced failure modes. Find half the time I won't do up a lock-ring is because of old clipsal receptacles and cheap chinese plugs which never seem to go together cleanly.

I hope your mate does not use side cutters to strip the wire insulation..... I have seen many electricians do this, especially those that save on using ferrules.

Yes, in the European Union the use of ferrules is a condition for certification. Here a link to what I consider a good, short, easy to read pdf article on the benefits of using ferrules. Its from a well known ferrule manufacturer:
http://www.weidmuller.com.au/baustei...e=downloadfile

Hi
I have many 3phase items and have replaced plugs and sockets due to "corrosion" of a pin. I say corrosion but it probably started by getting wet or hot and discolours. Could be spread contacts due to wiggling. But if they are not noticed and replaced or cleaned will get hot and worse. My mill had a plug and socket for the main motor and a European type that had over the years of heat etc stuck together so both halves had to be replaced as one.
When removed and busted apart for curiosity it was just one pin that was fused together, the others were like new.
James


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Originally Posted by cba_melbourne

I hope your mate does not use side cutters to strip the wire insulation..... I have seen many electricians do this, especially those that save on using ferrules.

Yes, in the European Union the use of ferrules is a condition for certification. Here a link to what I consider a good, short, easy to read pdf article on the benefits of using ferrules. Its from a well known ferrule manufacturer:
www.weidmuller.com.au/bausteine.net/dav/showdav.aspx?domid=1031&sp=B&awpfad=http%3a%2f%2fcmswebdav.weidmueller.de%2fcms%2fgu_mx%2fwhite+papers%2f&rooturl=http%3a%2f%2fcmswebdav.weidmueller.de%2fcms&awname=Weidmuller_Ferrules_White_Paper.pdf&type=downloadfile

I think you must be rather naive in the trades! If anyone here or elsewhere claims never having used less than the approved tool, you've either found a saint, or a liar....and I'm inclined to the latter.

Originally Posted by Hunch

I think you must be rather naive in the trades! If anyone here or elsewhere claims never having used less than the approved tool, you've either found a saint, or a liar....and I'm inclined to the latter.

You see it all the time, I've done it myself, and also most electricians have their marvel pliers within easy reach But never ask them if they have ever nicked a wire, you might get a smack in the teeth.

Funny that...

Ray

Originally Posted by Hunch

A mate who worked at the steel mill on their rather large currents - and more often than not, live - is a firm believer in not using pins/ferrules, with their other introduced failure modes. Find half the time I won't do up a lock-ring is because of old clipsal receptacles and cheap chinese plugs which never seem to go together cleanly.

We have some plugs like that. Straight instead of angled and the ring feels softer than the clipsals. They are supplied on equipment as delivered. Only clipsal is kept on site so they only last until they get replaced. I suspect that some may need replacing earlier than normal. I ran a plug over with a forklift once and was annoyed that it was a clipsal. Dean