Quick Question re: Garage

[scotcruz]

Hi folks,

I have a radial circuit to the garage. Its on a 16A MCB using a 2.5mm T&E. Currently there are 2x1 gang sockets and 2x2 gand sockets as well as a 3A spur for the combi boiler.

I am looking to stack the dryer and the washing machine in the garage and wanted to check if it's OK or do I need to get a 20A MCB?

Please advise

 

[JohnW2]

I have a radial circuit to the garage. Its on a 16A MCB using a 2.5mm T&E. Currently there are 2x1 gang sockets and 2x2 gand sockets as well as a 3A spur for the combi boiler. .... I am looking to stack the dryer and the washing machine in the garage and wanted to check if it's OK or do I need to get a 20A MCB?

Are you planning/envisaging using the dryer and WM simultaneously?

Kind Regards, John

 

[scotcruz]

Thanks John, Likely yes.

 

[JohnW2]

Thanks John, Likely yes.

If both are on simultaneously, then there will certainly be times when the total load would exceed 16A - so, as you suggest, it would be advisable to change the MCB to 20A. Unless it is deeply buried in thermal insulation or suchlike, the 2.5mm² cable should still be OK on a 20A MCB.

Kind Regards, John

 

[scotcruz]

Super, thanks for the advice.

 

[winston1]

Don’t plug them both into the same 2 gang socket.

 

[scotcruz]

Don’t plug them both into the same 2 gang socket.

Thanks, the dryer and washing machine will be plugged in 1gang double pole socket each.

 

[Vicario]

Winston. I have a dishwasher and washer dryer plugged into a double socket under the sink. If we're drying our laundry we sometimes use the dishwasher. Is this not allowed? What is the reason....I never realised that there are rules about what you can plug in, provided you stuck to the 13 amp limit for each. Thanks.

 

[scotcruz]

Winston. I have a dishwasher and washer dryer plugged into a double socket under the sink. If we're drying our laundry we sometimes use the dishwasher. Is this not allowed? What is the reason....I never realised that there are rules about what you can plug in, provided you stuck to the 13 amp limit for each. Thanks.

It's about the current draw.. your double socket is rated and tested at 13A. If you run both simultaneously and if the current draw is higher than 13A you are putting too much load.

Hence why I have 2x1 Gang sockets each at 13A to let me run the washing machine and dryer simultaneously

 

[bernardgreen]

provided you stuck to the 13 amp limit for each.

which would be a total load of 26 Amps.

Most double sockets are tested and thus rated for a total load of 20 Amps with one socket "overloaded" at 16 Amps and the other socket loaded with 4 Amps.

https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=59856

BS1363-2:1995 requires for double socket outlets that both socket outlets have loads applied via test plugs, 1 test plug having a load of 14 amps whilst the other has a load of 6 amps, making a total load of 20 amps on the cable supplying the double socket outlet. The double socket outlet is then subjected to this loading for a minimum continuous period of 4 hours or longer until stability is reached with a maximum duration of 8 hours (stability being taken as less than 1 degC rise within 1 h). The test is passed if neither the terminals / terminations, nor the accessible external surface, increase in temperature by more than 52 degC.

 

[Vicario]

Are there plugged in appliances that safely draw 16 amps? I've seen posts on here about electric ovens which have to be hardwired because they draw more than 13 amps. My Neff is rated at 2.99kw so comes with a plug! Thanks for all the advice, I'll just use one appliance at a time from now on. I wonder why this rule isn't more widely advertised as presumably there must be ovens plugged in next to a kettle in many homes.

 

[Adam_151]

In reality, it doesn't cause a problem unless you are trying to load both sides up constantly, I've seen a retail site where there were problems with the heating and to get a temporary solution 8 x 3kw downflow heaters were fitted in 4 locations, spaced a couple of meters apart and blowing separate directions, each pair of heaters was plugged into a twin socket outlet fed via a 32A breaker on 4mm cable. Every socket had signs of thermal damage a few years later (you know what they say about temporary solutions)

So 2x 13A constantly is a problem, lower or more intermittant loads are less of a problem, dryers are generally one to be concerned about as they pull about 10 to 12A contstantly for the drying cycle, washers and dishwashers less so as they have a period of heating the water, then slosh it around for ages, but there could be an issue if there is a dryer on the other side while it is heating. Kettles not really a problem as the only run for a few minutes, unless you are a cafe then it might be a problem, plug in electric car chargers are an issue as they draw 10A for hours on end (manufacturers limit to 10A in most cases, as 13A was found to cause issues)

I wouldn't worry about washer and dishwasher in same socket as heating cycles are not likely to co-incide with each other enough to cause a problem, so perhaps just avoid running the machine on drying when dishwasher is in use.

 

[JohnW2]

In reality, it doesn't cause a problem unless you are trying to load both sides up constantly ...

It's apparent that experiences vary considerably.

For what it's worth, my personal experience is more than consistent with what you suggest. For very many years, I had a washing machine and dryer plugged (often used simultaneously) into one double socket, and never saw even the slightest sign of any thermal damage to plugs or sockets as a result. On the other hand, there seems to be no doubt that some people do experience thermally-damaged plugs/sockets in that situation.

What seems ridiculous to me is that BS1363 only requires the temperature-rise test to be undertaken with 20A total (14A + 6A), since I would suggest that almost no members of the general public would think that there was any problem in plugging two 13A loads into the two "13A outlets" of a double socket.

One might think that the explanation relates to history, in that when BS1363 was first written, there were probably few, if any, domestic dwellings that even had two 3kW loads that they could plug into a double socket, so that testing at 20A seemed reasonable for domestic use (and that has never been 'updated' over the years/decades). However, since BS1363 plugs/sockets have never been exclusive to domestic installations, I'm not sure that that explanation holds a lot of water, since multiple 13A loads undoubtedly exist in many commercial and industrial environments.

Kind Regards, John

 

[JohnW2]

... Most double sockets are tested and thus rated for a total load of 20 Amps with one socket "overloaded" at 16 Amps and the other socket loaded with 4 Amps.

As the extract from BS1363-2 you go on to quote says, it's actually 14A + 6A - but, as you say, the total is only 20A.

As for your "... tested and thus rated for a total load of 20 Amps ", whilst it may be close to true in practice, that "thus" is by no means an inevitability - at least, in terms of the testing undertaken to confirm compliance with BS1363.

There's obviously nothing stopping a manufacturer producing a product which exceeds the minimum requirements of BS1363 and hence 'rating' it (on the basis of their tests) at more than 20A. Indeed, I would imagine that few, if any, will be sailing so close to the wind that they producing products which would fail the BS1363 test at, say, 20.5A or 21A - and some may even pass the test at 26A.

Kind Regards, John

 

[plugwash]

On the other hand, there seems to be no doubt that some people do experience thermally-damaged plugs/sockets in that situation.

Though sometimes people experience thermally damaged plugs and sockets with only a single plug in a single socket..........

One might think that the explanation relates to history, in that when BS1363 was first written, there were probably few, if any, domestic dwellings that even had two 3kW loads that they could plug into a double socket, so that testing at 20A seemed reasonable for domestic use (and that has never been 'updated' over the years/decades). However, since BS1363 plugs/sockets have never been exclusive to domestic installations, I'm not sure that that explanation holds a lot of water, since multiple 13A loads undoubtedly exist in many commercial and industrial environments.

It was also written in a time when H&S wasn't anything like as extreme as it is today.

I think there is a big difference between how safety authorities view new things and existing things. New things are often viewed with a paranoid attitude, existing things are viewed based on how much of a problem they seem to be causing in practice. Presumablly the safety authorities have not seen enough issues caused by overloaded double sockets to push for changing the standards.