BEWARE - why do extension cords melt?

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Re: BEWARE - why do extension cords melt?

Postby YarraRanges » Thu Aug 09, 2018 2:24 pm

As an electronics technician I was taught that you must NEVER EVER tin the end of a wire with solder that is going to be held in a screw terminal.
Compressing the solder causes micro cracks in the solder where corrosion will eventually occur. Crystalisation can occur in these areas and multiple small diodes can be created by the corrosion causing heating and eventual failing of the termination.

Remember NEVER EVER tin a copper wire that is going to be held in a compression screw terminal!
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Re: BEWARE - why do extension cords melt?

Postby Shano592 » Wed Nov 25, 2020 8:04 pm

I'm going to bump this thread...

Moving house this week, I finally had to dismantle the Gin Genie Mk11 into storage mode. Where I am now is temporary, so it sits in a long-span rack, along with the coffee roasting gear. The updated boiler has 2x FSD 2400W stainless, weld-free elements that run really nicely, and are great in concert. One sits at about 10 litres from the bottom, while the other is at about 25 litres. 50 litres boils up in under an hour, and I generally shut down the upper one after reflux.

With the 2 elements, I have had to run the still across 2 circuits in the house. No biggie to date, as the house I was looking after actually had 5 power circuits, so there was never a shortage of choice. For each boiler, I would run a separate cable from the house or garage, to the back shed. This has served me really well, as I can pack the whole thing down, with no evidence that I was ever there... (The back shed is a double garage, but is un-powered)

Now, to packing down. The last thing I grabbed upon packing away the whole shebang, was the power lead that had been in use since the Gin Genie Mk1 came to life. Pushing 21-2200W through a domestic extension 10A lead over many hours at a time over many months, had it's cost. The lead - upon inspection - was torched. Both ends had clear connection plugs, so you could see very plainly how badly charred the insides were. At each end was a single affected connector, and it was black, going right back into the plug. The house is fitted with an RCD, and I never left things unattended. In fact, a lot of pizzas were consumed, watching and measuring...

I can't be 100% certain, but I cannot imagine that this lead would have gone too much longer without some kind of catastrophic failure... most likely going down/up in flames.

Check ALL of your equipment regularly, ladies and laddies! Your assembly is only as good as your worst component.

FWIW, I ended with around 4500cc @ 92% from the last run, so I have a little in reserve until the Gin Genie Mk11 is back in action... That's on top of the 3L of gin, the 5L rum barrel, 2 more bottles of rum, 5 bottles of mulberry wine, 5L of 15% ABV ginger beer, plus a little more vodka... Christmas is sorted.
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Re: BEWARE - why do extension cords melt?

Postby Sam. » Wed Nov 25, 2020 11:27 pm

Yep good reminder Shano, if your going to put all the effort, time and money into this hobby make sure you fork out for a decent extension lead :handgestures-thumbupleft:
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Re: BEWARE - why do extension cords melt?

Postby Tesla101 » Thu Nov 26, 2020 7:22 am

Most of the stress on electrical components is caused during the initial micro second of switch on. The components need to be able to handle that initial surge current. Poorly fitted or terminated components may arc which causes charring.

For safety, components should be selected with a rating well above their intended use. For a 2200W load on a 240V circuit I'd opt for a 15A extension cord, rather than a 10A.

It's also good practice to test the cord temperature during use. If the cord feels warm to the touch then it's under-rated for that task and should not be used.

Safety should always be our number 1 priority.
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Re: BEWARE - why do extension cords melt?

Postby OzDistilling » Fri Nov 27, 2020 9:01 pm

The quality of extension cords sold in this country is variable. Regardless of the fat outer sheath, inside their maybe less than acceptable conductor sizes.

Always buy such high demand extension cables from a Electrical Supplier, not Bunnings or Woolies.

The key to high current extension cables (or any hgh current wiring) is to overrate. Use the next size up.

A standard 15A lead should have a minimum conductor size of 2.5mm2, and handle a 3600 watt heater. But this is the rated maximum. The longer the cable, the higher the resistance, the more heating effect.

For a 15A/3600W heater I would choose a 4mm2 cable, rated for 30-32 A. You cant buy these made up :-( But your local sparky will make one for you.

So overrate. keep it short, use quality connectors.
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