RCD / LED problem

[Richard Burns]

Theoretically the LEDs cannot be affecting the RCD on a different supply as the RCD is only monitoring the outgoing circuits.
Possibly, but I am not sure how, the LED dimmer is introducing a DC component that is masking the RCD operation; alternatively if there is a Neutral Earth fault on the sunbed side of such resistance that is just tripping the RCD and there is also a neutral earth fault on the LEDs once switched on then this would give parallel paths for the neutral current and so reduce the current seen by the RCD below its tripping threshold.
If the sunbeds are switched on by a double pole switch then it is possible that there is a difference in arcing across the poles so that the RCD occasionally thinks there is an imbalance and the LEDs just happen to coincide with the trip times. This could be tested by connecting the "working" sunbed to one of the other sockets.

 

[johnduffell]

So when the LEDs are on, the RCD doesn't trip? All one one RCD?
If so it could simply be the sun beds are leaking inductively to earth and the LEDs are leaking capacitively. So they cancel out enough to stop a trip. Not sure how well RCD trip if you leak imaginary power, but either way the above suggestions about one 3p RCD per bed make sense.

 

[Deleted member 26818]

So when the LEDs are on, the RCD doesn't trip? All one one RCD?
If so it could simply be the sun beds are leaking inductively to earth and the LEDs are leaking capacitively. So they cancel out enough to stop a trip. Not sure how well RCD trip if you leak imaginary power, but either way the above suggestions about one 3p RCD per bed make sense.

Did you test the RCD?
Did you test the RCD with the LEDs on or off?

 

[johnduffell]

Did you test the RCD?
Did you test the RCD with the LEDs on or off?

I guess that was aimed at the op, not to me

 

[Deleted member 26818]

I guess that was aimed at the op, not to me

Sorry, thought you were the OP.
You need a picture.

 

[johnduffell]

You need a picture.

Good point, never intended to hang around here long enough to need one, but turns out you lot are more welcoming then i expected

 

[Wilko]

Hi - The shop's LED lights with no functional switch caught my eye - an indicator perhaps the rest of the place isn't wired as we might expect?

 

[Octopus]

Hi - The shop's LED lights with no functional switch caught my eye - an indicator perhaps the rest of the place isn't wired as we might expect?

I was wondering this but he has stated the new rcd board is wired independently of the existing cu which supplies the led light circuit ......

Very odd

Hope we get feedback once he’s been back on site ..

 

[marconi]

http://www.solansunbeds.co.uk/How_to_Set_up_a_Successful_Tanning_Salonv1.2.pdf

See page 16 of 17 of the reference which is quite clear that if RCD protection is provided for Solan sunbeds then the trip current difference must be 100mA and not 30mA to take into account the accumulated leakage from the many ballasts and hot humid ambient air inside the equipment. What do the technical installation instructions say for the make and model of tanning machine for which you have provided electrical supplies?

 

[Wilko]

Gives a good insight as to why RCBO should be used for each one. Hopefully 30mA rating will be ok, as I'm not overjoyed at the idea of stepping in and out of a metal box with 100mA ... (is it just me?) Still no clue as to the LED role in all this .

 

[johnduffell]

overjoyed at the idea of stepping in and out of a metal box with 100mA

True but as long as you trust the earthing (and any supplementary bonding if you like) you should be disconnected within a few seconds if there's a fault, and the touchouch voltage shouldn't be too high.
I'd be more worried about all that 17kw of uv coming from the tubes tbh, it'd be factor 50 for me!

 

[Wilko]

Being born in a sunny place (and seen the results) I think these things are just plain crazy .

 

[marconi]

See #13 - The OP says each bed is connected to its supply by a 5 pin interlocked plug and socket. Is this acceptable if a 100mA RCD is used? I don't know if it is and whether instead each bed must be 'hard-wired' in.

 

[Deleted member 26818]

Would be acceptable if the plug and socket is rated above 20A or if the sockets are labled up.

 

[Chris1234]

As above, power circuits with sockets of 16A and below require a 30mA RCD.

Presumably if he has 32A MCB’s then he is using 32A sockets.