Best brand of RCD sockets

3) With a passive RCD one must ensure if the load is high enough to reduce the voltage to below what the RCD will operate at either that voltage is safe or some other device will trip. One would hope that voltage would be 50 volt or less it seems RCBO's to BS EN 61009 do but I know I had problems trying to use an RCD designed for 230 volt on a 55 – 0 – 55 volt supply. However one hopes that where the loop impedance satisfies the required limits then the fuse or MCB will trip where the load is high enough to reduce the voltage to below what the RCD will work at?

5) With TT there should already be a RCD. With TN if the item is correctly bonded then the fuse/MCB should be enough to protect against direct contact. I would agree a water leak could result in a fault being transmitted outside the protective cage formed by the metal casing of the washing machine.

I will agree a RCD can become faulty. But in the past I have found with a new RCD when they fail often taking the tension out of the cables will then mean they work. The casing it seems can warp and cause them to fail. However with a plug in unit the unit is in general more robust so less likely to be warped to a point where it will fail.

I don’t say don’t use a RCD but a plug in RCD starts at £5 but a RCD socket at around £15 so why spend three times over what is required? The guy says he’s short of money so it seems daft to spend 3 times the money with the only gain being it could comply with regulations but without a minor works certificate then it will not comply any way so why bother fitting a RCD socket rather than a simple plug in RCD?

Thanks for neatness I am having to chop the plug of one of the appliances anyway, so it makes sense to wire into an RCD plug. However the sockets could do with been replaced as they are old and scruffy and the CPC wire needs sleeving etc (the spark never bothered using sleeving or gromits!).

It is the washing and dish washer I am more concerned about due to the possible contact with water and electricity. I will replace the sockets with standard MK ones and just use the plugs, cheaper and easier to replace if they become faulty too!.

ericmark said:

3) With a passive RCD one must ensure if the load is high enough to reduce the voltage to below what the RCD will operate at either that voltage is safe or some other device will trip. One would hope that voltage would be 50 volt or less it seems RCBO's to BS EN 61009 do ... However one hopes that where the loop impedance satisfies the required limits then the fuse or MCB will trip where the load is high enough to reduce the voltage to below what the RCD will work at?

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Quite. As I said, unless it's a TT installation, then one should not be relying on an RCD to deal with full-blown ('negligible impedance') L-E faults, which will be cleared by an OPD. Such a fault, particularly if close to the RCD (and even more particularly with TN-C-S) will obviously reduce the L-N pd seen by the RCD to a very low level, at which the electronics of a passive RCD may not work - but I wonder whether there is perhaps a capacitor which, under those circumstances, maintains supply to the electronics for long enough for the RCD to operate (which, after all, is only a small fraction of a second)

ericmark said:

5) With TT there should already be a RCD. With TN if the item is correctly bonded then the fuse/MCB should be enough to protect against direct contact.

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As I said, an OPD is of no help to someone who finds themselves in the unfortunate position of providing a path between L and E. In a TT installation, the fuse/MCB will usually provide no protection against a low impedance L-E fault - that's obviously why TT installations need RCDs.

ericmark said:

I will agree a RCD can become faulty. But in the past I have found with a new RCD when they fail often taking the tension out of the cables will then mean they work. The casing it seems can warp and cause them to fail. However with a plug in unit the unit is in general more robust so less likely to be warped to a point where it will fail.

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On the other side of that equation, a plug-in one will, or can be, subjected to much more 'rough handling' than a fixed-wired one.

ericmark said:

I don’t say don’t use a RCD but a plug in RCD starts at £5 but a RCD socket at around £15 so why spend three times over what is required?

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A good question, but I also wonder how happy I would be to trust my life to a fairly complex bit of (hopefully) precision engineering which cost only £5, and which might possibly get a lot rougher in-service treatment than a 'fixed' RCD!

ericmark said:

The guy says he’s short of money so it seems daft to spend 3 times the money ... so why bother fitting a RCD socket rather than a simple plug in RCD?

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Fair enough - but I don't think we've really discovered why the OP feels the need to provide (only) his washing machine with RCD protection of any type, or cost.

Kind Regards, John

He says that he is

RI1982 said:

concerned about due to the possible contact with water and electricity.

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But this crazy. There are more (and greater) risks elsewhere in the house.
There's very little risk if the appliances are properly earthed.

Dear OP. There are other things that you should be worrying about.
Maybe you should be putting hazard warning tape on every step on your stairs!

Taylortwocities said:

He says that he is

RI1982 said:

concerned about due to the possible contact with water and electricity.

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I realise that, but as you go on to say ...

Taylortwocities said:

But this crazy. There are more (and greater) risks elsewhere in the house.

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...which is clearly true.

Taylortwocities said:

Dear OP. There are other things that you should be worrying about. Maybe you should be putting hazard warning tape on every step on your stairs!

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Quite so.

Kind Regards, John

AndyPRK said:

333rocky333 said:

Also be aware that some are non latching and need resetting after power failure which may be undesirable

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Like MK one. I couldn't believe it.

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Mk do both types, see page 4 of https://www.mkelectric.com/Documents/English/EN MK Catalogue/Logic Plus.pdf ("active" means it needs resetting after power failure, "passive" means it doesn't).

AndyPRK said:

333rocky333 said:

Also be aware that some are non latching and need resetting after power failure which may be undesirable

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Like MK one. I couldn't believe it.

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Why not?