Flickering red light

BarelySentientAI

cherry76 said:

BarelySentientAI said:

That's still three high-power appliances into a single extension though, isn't it?

Doesn't really fix the problem.

They are not used at the same time. The other option is to plug and unplug after each use.

AKA the option that doesn't burn your house down.

Grenage

To be fair, it's better than the cube.  It's also safe in practice as long as there is no concurrent use.

casper_gutman

Grenage said:

To be fair, it's better than the cube.  It's also safe in practice as long as there is no concurrent use.

Especially as they're all connected via a single 13A fuse which, though not perfect, would probably avoid the worst outcomes if two devices were used simultaneously (assuming the OP hasn't replaced the fuse with a paperclip!).

Ectophile

casper_gutman said:

Grenage said:

To be fair, it's better than the cube.  It's also safe in practice as long as there is no concurrent use.

Especially as they're all connected via a single 13A fuse which, though not perfect, would probably avoid the worst outcomes if two devices were used simultaneously (assuming the OP hasn't replaced the fuse with a paperclip!).

I think it would have to be three appliances to blow the fuse.  I have seen someone fill two kettles with water and plug them both into a 4-way extension lead.

The outcome? Two kettles of boiling water.

13A fuses are extremely reluctant to blow for anything less than a short circuit.

ThisIsWeird

Eek!
You might get away without blowing a 13A if the two kettles are 2kW each = ~17A, but surely not if they are 3kW jobbies?
Either way, even a 17A pull on a mains plug is putting all the contacts under some stress. 

Niv

cherry76 said:

ThisIsWeird said:

BarelySentientAI said:

ThisIsWeird said:

cherry76 said:

Sorry for the confusion, the cube with 3 plugs and one by the side are in the kitchen. The second one with multi plug is plugged in main socket in my bedroom for computer, printer and a few others. 

Why did you show us two completely different setups, when enquiring only about one?
But, good that you have,....

They did ask two different questions - very confusingly, but they did.

1.  Flickering red light when I switch computer on. Shall I be concerned?

2.  Been advised not to use cube for extension.  Thoughts pl!

As you say, lucky they did though, because the second one is far more concerning than the first.  Don't put three 10A devices in a 13A rated adaptor, particularly when it's likely more than one will be used simultaneously.

Oops, thanks, missed that :-)

This is the new set up, have got rid of the cubes.

It is not a good idea to have anything designed to heat plugged into an extension lead. 

My sis did this and the extension lead melted... no fuses blew.

You have been warned. 

Niv

cherry76 said:

BarelySentientAI said:

That's still three high-power appliances into a single extension though, isn't it?

Doesn't really fix the problem.

They are not used at the same time. The other option is to plug and unplug after each use.

That is what I would do or, if available, plug into their own sockets even if it means relocating the appliance or get additional sockets installed by an electrician. 

victor2

I know a builder/electrican who had done some work in a customer's house and got an angry call the following Sunday telling him he'd damaged their electrics as the RCD kept tripping and wouldn't reset.

He went to investigate and found the owner had plugged a coiled up extension lead into a socket and plugged a fairly heavy duty appliance into it. The owner had unplugged the appliance but not the extension lead, which had melted inside and was still tripping the RCD. No fuses blew, but it was too much for one of those "wind up" extensions we all find so useful.

Result was irritated builder and embarassed customer!

casper_gutman

ThisIsWeird said:

Eek!
You might get away without blowing a 13A if the two kettles are 2kW each = ~17A, but surely not if they are 3kW jobbies?
Either way, even a 17A pull on a mains plug is putting all the contacts under some stress. 

I looked it up as I was curious. A 13A fuse compliant with BS 1362 must be capable of carrying a current of 1.6 times the rated current (so 20.8A for a "13A" fuse) for at least 30 minutes without blowing, and must blow within 30 minutes when it sees a current that exceeds 1.9 times the rated current (24.7A for our nominal 13A fuse). 
Why does a 13A fuse not blow at 13A? (pat-testing-training.net)

In practice the voltage in the UK is usually around 240V (it's specified as 230V +10% or -6%). Two 3kW kettles will draw about 6000/240 = 25A*, and will only be on for a couple of minutes, so in practice you're probably unlikely to blow a 13A fuse by connecting two 3kW kettles.

I like to imagine people cleverer than me have thought all this through, and the cables and sockets are all correspondingly over-specified so this sort of thing won't cause a problem. It's probably not a great idea to rely on that routinely, though....

*Edited to correct unit from V to A.

BarelySentientAI

casper_gutman said:

ThisIsWeird said:

Eek!
You might get away without blowing a 13A if the two kettles are 2kW each = ~17A, but surely not if they are 3kW jobbies?
Either way, even a 17A pull on a mains plug is putting all the contacts under some stress. 

I looked it up as I was curious. A 13A fuse compliant with BS 1362 must be capable of carrying a current of 1.6 times the rated current (so 20.8A for a "13A" fuse) for at least 30 minutes without blowing, and must blow within 30 minutes when it sees a current that exceeds 1.9 times the rated current (24.7A for our nominal 13A fuse). 
Why does a 13A fuse not blow at 13A? (pat-testing-training.net)

In practice the voltage in the UK is usually around 240V (it's specified as 230V +10% or -6%). Two 3kW kettles will draw about 6000/240 = 25V, and will only be on for a couple of minutes, so in practice you're probably unlikely to blow a 13A fuse by connecting two 3kW kettles.

I like to imagine people cleverer than me have thought all this through, and the cables and sockets are all correspondingly over-specified so this sort of thing won't cause a problem. It's probably not a great idea to rely on that routinely, though....

The pound shop extension lead or chinesium adaptor might not be quite so over-specified as you hope.

Older domestic wiring might not be either.

Not a great idea to deliberately overload things, even if it's been "safe" so far.