RCD tripping a mystery

[Chrisknowlesuk]

Hi

I have an issue with random RCD tripping. It happens at different times of the day and no obvious cause (ie particular piece of equipment).

All connected equipment has passed recent PAT test and IR on circuit looks ok (>600M PE).

A lot of the connected equipment has thermostat controlled heating elements - wax melting machines etc (it’s a beauty salon).

Had a thought that if a couple of RCD protected socket adapaters were put on the sockets and checked whenever it tripped, Does this sound like a reasonable albeit long winded way of narrowing down the fault??

Any other suggestions??

 

[telectrix]

if you are thinking of the plug in type, you could get some 10mA ones. if it's appliance problem that would sort it. as long as you can rely on hair-brained beauticians to plug them in.

 

[sevuk]

if you are thinking of the plug in type, you could get some 10mA ones. if it's appliance problem that would sort it. as long as you can rely on hair-brained beauticians to plug them in.

Will achieve better discrimination that way. Good idea.

 

[Octopus]

I would ask the customer to keep a log of when the tripping occurs.

What's the background leakage on the circuits protected by the RCD ?

You could have high leakage and anything could tip it over ....

What are the RCD test results?

 

[Chrisknowlesuk]

Have got s couple of 30mA plug in RCD adapters, hopefully they will still work.
Haven’t run tests on RCD in board yet.

Been promised free Manicure and spray tan if I cure the problem....

 

[telectrix]

spray tan. you poufff!.

 

[Jim90]

Not the same place they do ‘happy endings’ after a dodgy massage? If so, where abouts is this place? My mate wants to know

 

[Chrisknowlesuk]

Hmm... unfortunately not, otherwise payment in kind..

As for spray tan and manicure I was only kidding - my finger nails are past it!!

 

[Octopus]

Haven’t run tests on RCD in board yet.

Hum ............ best you do that first, then probably some IR tests and a background leakage test.

Do you think we have crystal balls?

 

[Chrisknowlesuk]

I think they have crystal balls?? But that’s probably to aid relaxation ....

 

[static zap]

Drive by, check for steamy windows !
( I have no idea what equipment they would have. )

 

[marconi]

For us to be informed on the installation could you also tell us:

1. the type of earthing system.
2. presence and state of EP bonding.
3. computer equipment?
4. any water leaks recently?
5. what kind of lighting?
6. how for example the wax baths are supplied.

 

[PEG]

if you are thinking of the plug in type, you could get some 10mA ones. if it's appliance problem that would sort it. as long as you can rely on hair-brained beauticians to plug them in.

I'm not sure you could guarantee discrimination using that method.

Just out of interest,has anyone else tested any of these plug-in RCD adapters? I did,on one me dad had purchased from B&Q and the best description i could give it,would be "random"

 

[stevethesparks]

You mention
"All connected equipment has passed recent PAT test and IR on circuit looks ok (>600M PE)"
Have you done a NE insulation check?

 

[static zap]

....... tested any of these plug-in RCD adapters?

Not tested , but some bargain ones seemed to have horrible hot spots on one side of them.
(Local supply hovers 245/250)
Possibly only for short-term use !

 

[I2C]

Hi

I have an issue with random RCD tripping. It happens at different times of the day and no obvious cause (ie particular piece of equipment).

All connected equipment has passed recent PAT test and IR on circuit looks ok (>600M PE).

A lot of the connected equipment has thermostat controlled heating elements - wax melting machines etc (it’s a beauty salon).

Had a thought that if a couple of RCD protected socket adapaters were put on the sockets and checked whenever it tripped, Does this sound like a reasonable albeit long winded way of narrowing down the fault??

Any other suggestions??

RCD Socket-Outlets
If you have socket-outlets which contain an RCD, it's important to ensure adequate discrimination has been provided. For example, if a socket-outlet containing a 30mA RCD is installed on the same circuit which is protected by another 30mA RCD at the consumer unit; it's possible that either of the RCD's will trip. Therefore, it's important to ensure discrimination is provided (delayed/higher value RCDs fitted at the source).

Earth-Leakage
Some appliances can 'leak' current to earth during use, which is known as an 'earth-leakage'. Often, the earth-leakage value is very small and insignificant on it's own, however if there are many appliances used which all contribute earth-leakage, the total value will increase and can trip a RCD (normally rated at 30mA).

RCD Testing
It's worthwhile performing tests on the RCD to ensure correct operation. This can include a ramp-test to determine the current required to trip the RCD and confirm functionality.