radial circuit to power washing machine, dryer and dishwasher

[Loky11]

Now chaps,

Will a radial circuit on a 20amp rcbo be enough to power a washing machine, dishwasher, dryer and fridge freezer?

At the moment the radial has a 2 gang to power 2 appliances and a 1 gang to power fridge freezer, possibility of spuring of this circuit to power an extra appliance?


Cheers.

 

[buzzlightyear]

Yes is the answer has long has you keep with in tha rating of the rcbo.

 

[telectrix]

bear in mind diversity.

not all appliances will be drawing power at the same time .

 

[Loky11]

Thanks buzz, I did think it would be OK, however I was concerned if all running at the same time it would keep tripping.

 

[Deleted account]

I wouldn’t.

Theoretically yes it would work, but good design would put a kitchen circuit as a separate ring from the rest of the house Due to the high loads On appliances.

3 of the highest loads on the property on a 2.5mm, I would say is boardering on not good design.

A 4mm radial I would be happy with.

edit: one other point I would make is I never put 2 high load appliances on one 13A double socket. From experience of many call outs they tend to burn out Over time.

 

[telectrix]

I wouldn’t.

Theoretically yes it would work, but good design would put a kitchen circuit as a separate ring from the rest of the house Due to the high loads On appliances.

3 of the highest loads on the property on a 2.5mm, I would say is boardering on not good design.

A 4mm radial I would be happy with.

butOP might have a separate ring for the rest of the kitchen sockets and wanting the radial just for these appliances?????

 

[Deleted account]

butOP might have a separate ring for the rest of the kitchen sockets and wanting the radial just for these appliances?????

Those 3 appliances alone pretty much are the vast majority of a kitchens load on a normal kitchen ring. Putting them on a radial is lowering the current carrying capacity considerably.

Having a ring for the rest of the kitchen wont take that much load away.

i accept design and calc wise it is acceptable, but i would like to give it that bit more current carrying capacity.

 

[Loky11]

The radial in question is in the utility, the kitchen has 2 separate radials with a total of 3 double sockets.
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I'm hoping to start my extension in the next couple of years so it will all be complete new design and re wire, not that it makes any difference haha

 

[pc1966]

Putting a fridge-freezer on a circuit with a higher than usual chance of tripping is not good, you go out for the day with something running and come back to find half your food is defrosting!

If rewiring/replacing then you could put in 4mm cable for a bigger radial, or if it is feasible add another 2.5mm run to the far end and turn it in to a ring, putting that on 32A breaker.

 

[telectrix]

i put fridges/freezers on either a dedicated RCBO or, if regs. permit, MCB.

 

[Loky11]

Never thought of that, what if I extended the radial to a fused spur then the extra appliance to the fused spur, if overloaded would that pop the fused spur or would it still trip the rcbo? This is temporary until the extension goes ahead.

 

[pc1966]

Just wondering out loud about "if regs. permit, MCB" for higher reliability (less nuisance tripping) for the power feed.

Obvious issues are RCD protection for buried cables less then 50mm from wall surface, so that can be mitigated with Flexishield cable more definitely than allowing others to install stuff.

What is the position on a 13A socket without RCD protection, is it OK if labelled and intended for use with a fixed appliance such as a fridge-freezer? Using a FCU would seem a lot of future trouble for the home owner for such an item.
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Never thought of that, what if I extended the radial to a fused spur then the extra appliance to the fused spur, if overloaded would that pop the fused spur or would it still trip the rcbo? This is temporary until the extension goes ahead.

Generally no, it won't help. Circuit breakers (MCB and RCBO) usually trip faster than fuses blow. Also there it is the concern of other things tripping (e.g. water leak for RCD).

 

[telectrix]

I also put the beer fermentation equipment on a non-RCD circuit. can't have the beer spoiling, can we?

 

[Zerax]

I also put the beer fermentation equipment on a non-RCD circuit. can't have the beer spoiling, can we?

I see you can easily buy a still these days... very tempting in these times of lockdown and reduced workload to have a play with that ! And it'll use up the potato peelings !

 

[Lucien Nunes]

if overloaded would that pop the fused spur

The fact that you are thinking about what will happen when the circuit is overloaded means the design is inadequate, never mind the F/F going off unexpectedly. As mentioned, appliances that use water have a higher than average probability of causing a leakage trip and automatic machines run unattended when no-one would be aware of the trip, so an ideal setup would not put them on the same circuit as the refrigeration.

The dryer is more or less a constant 2kW load, so if the washing machine and dishwasher heaters come on at once, the circuit will be overloaded at up to 30A. Although you can allow diversity when a large number of items are in use, two appliances that might be started on their programmes at the same time and heat water from cold for maybe 20 minutes at a time before their thermostats take effect, do not in my book constitute a diverse load. We often start multiple machines at once at home.

So no, I would not do this. A 32A radial could take more load in addition, as then you can legitimately start to apply diversity.

 

[Strima]

If I had to place all appliances like that on one radial circuit then it would be a 32 amp 4mm.

 

[Loky11]

If I had to place all appliances like that on one radial circuit then it would be a 32 amp 4mm.

Ideally yes, but replacing current radial with new 4mm will be very difficult, with tiled walls and floor lol

 

[Strima]

Ideally yes, but replacing current radial with new 4mm will be very difficult, with tiled walls and floor lol

20 amp it is then, advise the customer against running all appliances at the same time.

 

[telectrix]

our washer/dryer is in garage. , the dishwasher is bent over the sink. no problem.

 

[pc1966]

Ideally yes, but replacing current radial with new 4mm will be very difficult, with tiled walls and floor lol

Is there any other way to add another cable? What about going outside route for part of it using SWA?

When they talk about "replacing" you do not have to remove the old one - it could be reused as a dedicated feed for the F/F (assuming not on the same RCD at the CU).