radial circuit to power washing machine, dryer and dishwasher

[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).

 

[Loky11]

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).

No space on cu to add mcb or rcbo

 

[pc1966]

No space on cu to add mcb or rcbo

Could you run another cable though?

You could temporarily retire the 2.5mm but keep it for later re-use (assuming you ever get a new CU with more space), and at least go for a 4mm feed to allow a 32A radial there. That won't deal with the RCD trip risk issue, but it would overcome the marginal total current situation.

Going one step further, if you can feed something like SWA (or Flexishield) that does not require RCD protection then you could feed it off a MCB at the CU and then fit a "garage" style small CU in that area with a couple of RCBO to give some fault tolerance.

Yes, it is hard to get selectivity on over-current with a MCB feeding another MCB (the overcurrent part of an RCBO) but depending on the cable and system Ze value you might get away with quite a high trip for the feed (as it only has to provide short-circuit protection with a 5s clearance time) and a couple of smaller RCBO that if they trip per-appliance fault it is not really any more of a deal than the plug's fuse popping.

 

[7029 dave]

IMO that would be a poor circuit design, basically your are more or less relying on diversity of the circuit.