Three phase rcd protection

[Electric joe]

Hi guys, I am rewiring a commercial launderette with 3 phase machinery.



Does the machinery need to be RCD protected being in commando sockets.



The sockets are not accessible to the public and each circuit is being used for a specific machine.



With the price of three phase rcbos the customer is not happy

 

[suffolkspark]

Yes, but if the rcbos are cost prohibitive look at the outlets you can fit rcds in (as long as your supply cables dont already need it) probably be similar costs though so hes/shes gotta swallow it, or you cut the plugs off and wire to rotary isolators, also see what manufacturers instructions say

 

[pc1966]

3-phase RCBO are expensive and often take up extra space leading to "lost" slots in TPN boards, so you might well end up cheaper to use socket & RCD combinations as @suffolkspark suggests, or as we did for a couple of 3P A/C units to put the RCDs in a DIN box adjacent to the TPN board.

But if the equipment can be hard-wired to lockable isolators for maintenance that would be cheapest and least trouble overall.

 

[Julie.]

Don't forget though, there are a few reasons why rcd/rcbo are required, not just because they are socket outlets, so if the wiring is less than 50mm behind the wall etc. Then the rcd function needs to be at the feed end.

Surface wiring or protected cables(armoured or conduit/trunking) would be fine with the rcd at either end.

Surface cable to fixed equipment (no socket) then no rcd required.

 

[Electric joe]

Cables will be clipped to basket surface mounted, wiring the machines to lock off rotary isolaters is possible and was my next option.

So by wiring to the isolator rcd protection will not be required.

Cables will also be armoured

 

[James]

the manufacturer's instructions may specify an rcd must be fitted but other than that, your plan seems sound to me.