Adding Sockets to Garage RCD Fused Spur

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Hi,

I'm very new to electrics and want to know if the below is possible, and if not, how I might go about it?

In the garage right now there is 2.5T&E coming in to a 13A RCD Fused Spur and 1 x 2-gang 13A metal-clad socket - this is currently powering a freezer and (since this weekend) a washing machine. I want to add 3 further 2-gang sockets to this RCD Spur, in order to power:
  • Washing machine
  • Freezer
  • Under-counter fridge
  • Small stereo and hand-held power tools when needed
I've calculated that the permanently-located appliances will draw approximately 8A, based on 2000Wx13A (single phase AC), so I should be well under the rated 13A input from the CU to the RCD spur, no?

Please let me know if I've misunderstood, as I'm sure I have at some point.

Thanks
 

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What did you mean by "based on 2000Wx13A"? Typo?
I, too, suspected that it was a typo, and was intended to read something like "based on 3000W=13A".

However, the OP talks of 8A, and I would have thought that the washing machine alone could account for that - so, although the WM would not be on for long periods (hence no real problem), I would have expected the peak demand (for the items mentioned) to be appreciably in excess of 8A, wouldn't you?

Kind Regards, John
 
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Apologies for the misunderstanding. The Washing Machine (https://whirlpool-cdn.thron.com/sta...tion=inline;filename="Product-Data-Sheet.pdf") is rated at 1850W. I'm assuming about 400W for the Fridge and Freezer combined. I used an online calculator (assuming 230 single-phase AC power) to get to my 8A (actually, 8.3A) figure - though I may have calculated/assumed something wrong in the process.

Do you think 13A would be enough to power these devices, assuming the fridge and freezer are constantly on, and the washer is turned on twice a week?
 
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I suppose it might exceed 8A but only when the WM water heater is on - last one I mended had 1800W element - so not for long.
 
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Do you think 13A would be enough to power these devices, assuming the fridge and freezer are constantly on, and the washer is turned on twice a week?
Sure. Even if the total is a bit over 8A (for relatively short periods) when the WM heater is on, it will still be well under 13A.

Kind Regards, John
 
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Anything incorporating a motor will have a much higher current draw at start-up then when running normally, so your 8A estimate doesn't allow for current peaks. Will your FCU trip on short-duration overloads?
 
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Anything incorporating a motor will have a much higher current draw at start-up then when running normally, so your 8A estimate doesn't allow for current peaks. Will your FCU trip on short-duration overloads?
The fuse in an FCU does not 'trip' - if it gets adequately overloaded, it 'blows'.

However, if the start-up current of a washing machine were enough to blow a 13A fuse (the same 13A fuse that would be in an FCU), an awful lot of people would have a major problem :)

In passing, it takes around 22A flowing continuously to blow a 13A BS1362 (as in plug or FCU) fuse ever - and a lot more current than that if only for 'short duration'.

Kind Regards, John
 
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I guess a way to combat the overloading issue would be to just temporarily switch off the fridge. The fridge will only be used in the summer months when absolutely required (it's a secondary fridge primarily being used to chill beers and wines). I don't imagine I'll be drawing anywhere near 22A on the appliances I have. If/when I decide to use powertools in the garage I'll temporarily switch off the fridge though I think the fridge draw is negligable
 
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I guess a way to combat the overloading issue would be to just temporarily switch off the fridge.
As I recently wrote, I really don't think you have any reason to be concerned.

When the washing machine is running, 13A would be plenty for it plus the other items you mention, and if the start-up current of a WM were anywhere near being enough (and for long enough) to blow a 13A fuse (which is what nearly all WMs have in their plugs), we would definitely 'know about it'.

In fact, fridges/freezers, particularly older ones, may well have as large, if not larger, start-up currents than a WBWM, so switching it off (and back on) is probably not too clever an idea, anyway!

In any event, the very worst thing that would/could happen would be for the fuse to blow (before harm to anything else results - that's the purpose of a fuse) - and, as above, I really don't think that is likely to happen.

Kind Regards, John
 
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