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Why is it dangerous to chain power dividers? (sopuli.xyz)

submitted 8 months ago by [email protected] to c/[email protected]

15 comments fedilink hide all child comments

Besides putting too many devices on a single wall socket, that draw too much power, what is supposed to happen?

Like say I chain ten dividers and put a single vacuum cleaner at the end. Is that more dangerous than plugging it directly into the wall?

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[–] [email protected] 4 points 8 months ago (1 children)

It's complicated. If everything is rated properly, it's not really an issue, the problem is you can hook a 15A power strip to a 10A or less extension cord that then goes into the wall. The strip will let you plug in 15A worth of equipment but its upstream can only handle 10.

But if you have the right sized extension cords and power strip for your load it's fine. It's just, the average person doesn't really understand the nuances.

https://youtu.be/K_q-xnYRugQ

[–] [email protected] 1 points 8 months ago (1 children)

I've never heard of being able to plug a 15A into a 10A socket. Everywhere I've seen them, they are keyed to physically prevent this. What country are you in?

[–] [email protected] 2 points 8 months ago (1 children)

AFAIK in North America we only have 15A and 20A sockets. Don't know how the standards are in the rest of the world.

In NA, you can plug an extension cord only capable of 5A and it's still got the same standard 15A plug and socket on it. And that's where the common fear comes from: it's very easy in NA to overload an extension or power strip by simply plugging a 12A appliance like a microwave oven on an extension cord rated for 5A that then plugs in a 15A socket in the wall and there's nothing to save you there, the extension cord will melt, especially if it's very long.

The UK doesn't have such a problem because all their plugs have fuses in them, so a 5A extension would have a 5A fuse in the plug, so you're safe you can't overload it, it won't let you.

The EU and Australia probably have sane standards where it's not allowed to sell undersized extensions, plus they use 240V so most appliances use half the current which makes it less likely to have undersized wires.

In the end it comes down to the availability of accessories that doesn't prevent you from overloading them. If the whole chain is capable of the full current all the way to the breaker/fuse it's safe, even if you have a kilometer worth of extensions the breaker won't let you pull more.

[–] [email protected] 2 points 8 months ago

In Australia, for example, the earth pin on a 15A plug is taller than a 10. This lets you plug 10A rated extensions and appliances into a 15A capable socket, but not vice versa.

Amperages above that have dedicated plugs, and any available adaptors only go downwards in amperage limit, not upwards.

This of course doesn't stop people getting creative with a screwdriver, or from creating immense chains of small gauge extensions, but it certainly goes a long way to reducing risk.