Author Topic: QTV #8 - Connecting / Joining Electrical Wires  (Read 8896 times)

SeanB

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QTV #8 - Connecting / Joining Electrical Wires
« on: July 01, 2014, 12:30:09 AM »
https://www.youtube.com/watch?v=ZMEy0wHYT_c

Martin the electrician. Nice comparasion in the methods of DIY joining of house wiring. Wire nuts, connector blocks and the push in wire joins.

All I have used before, and I like the ceramic wire nut ( not available in the USA it seems, I should send Martin a pack or two of the 2 sizes commonly used in wiring here) and have tried the push in connectors as well, though for high current I am not going to use them, as they are likely to suffer long term from overheating. Lighting use they are fine, up to around 10A. I prefer for higher current use to use a solid copper crimp connector that is crimped around the cables then sleeved for insulation, or use the larger ceramic wire nuts.


Monkeh

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Re: QTV #8 - Connecting / Joining Electrical Wires
« Reply #1 on: July 08, 2014, 10:19:40 AM »
though for high current I am not going to use them, as they are likely to suffer long term from overheating.

Based on what?

SeanB

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Re: QTV #8 - Connecting / Joining Electrical Wires
« Reply #2 on: July 08, 2014, 12:18:25 PM »
The small contact area that touches the bare wire, along with a thin sheet to conduct is going to give issues with overheating at higher currents. You really want a large contact area with a screw that is deforming the wire to give a gas tight joint to the wire, so that the area in contact is large. I have met plenty of socket outlets with small contact areas inside, which burn out in short order with a current much above 5A, despite them being rated for 16A, and I have been changing them out with depressing regularity. As well the switches use small contacts, and these also burn out. Thus push on connectors are not a thing for high current use, as the contacts will burn.

Monkeh

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Re: QTV #8 - Connecting / Joining Electrical Wires
« Reply #3 on: July 08, 2014, 12:36:40 PM »
So the approvals are just for show, eh. The current bar in these things is >2.5mm˛, not a thin sheet. One I have here, rated for 24A, is well above 6mm˛. Wago connectors are gas tight. When they say 32A (which they don't in the US for other reasons), they mean it.

I've said this in the Youtube comments, and I'll say it here: Don't compare proper terminals with cheap crap built into cheap accessories.
« Last Edit: July 08, 2014, 12:38:20 PM by Monkeh »

SeanB

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Re: QTV #8 - Connecting / Joining Electrical Wires
« Reply #4 on: July 08, 2014, 02:11:05 PM »
Sad to say the last socket outlet I replaced failed and burnt open, right at the embossed certification logo. They are approved but the manufacturers are just cutting material costs and using thinner and thinner material, and are generally just using poorer materials. The old 40 year old sockets fail only after thousands of cycles, but the newer ones fail with very few cycles, and with a load they fail sooner. The 3 name brand manufacturers here are all in the same cost cutting business, and the no name stuff is so bad that you basically will not want to use it.

I am not saying that you cannot get a good push in fitting, but that they are going to be a very hard to check item without destroying at least one per batch to see if they have been cost reduced but still look the same. You might find after a while the solid bar has become a folded shaped stamping, and then over time the metal is thinned out slightly. Plugtops here used to have 3 pins in solid brass, then a version came out with a steel nickel plated earth pin, then they started to drill back the centre of the brass, and now you get them rolled out of nickel plated steel for all pins. Rolled brass sheet on some, and this is very thin, barely capable of surviving insertion into a new socket, and often they are at the short end of the specification. Still have the same quoted current of 16A, but I personally would not trust them past 5A. The latest is a version that is an adaption of the Swiss socket, with a 3 pin socket with a polarising offset on the centre earth pin. Those at least are solid brass, and have an insulating sleeve designed in, so are a safer plug for insertion live. They are also compatible with a standard double isolated 2 pin plugtop, like a cellphone charger. That use is why I buy them, no 2 pin adaptors that mysteriously go missing every so often.