rcd spur keeps tripping, fused spur working fine

[skhudy]

Hi, I changed some older sockets in the garage, and at the same time replaced the fused spur with an RCD Spur (13A 30mA) - the SafetySure one toolstation sell if it matters.

The RCD spur trips immediately and doesn't stay on. I thought it was faulty and replaced it, but the replacement does the same. I have rechecked and the fused spur stay on.

Why would the rcd spur keep tripping?

Thanks!

 

[PrenticeBoyofDerry]

Is there any load connected when it trips?
What condition was the existing circuit, since of any damage or moisture?
RCDs trip when there is earth leakage/imbalance between line and neutral currents.

 

[skhudy]

Is there any load connected when it trips?
RCDs trip when there is earth leakage/imbalance between line and neutral currents.

One of the sockets is a usb socket, but no load on any plugs, nothing plugged into the usb. I have also tried a different working usb plug socket just in case one was faulty

 

[PrenticeBoyofDerry]

check all socket backboxes and any junctions for trapped, damaged or damp cables.
Try unscrewing face plates from back boxes and pulling away with cables still connected to sockets, then see if the RCD will reset, if so this would suggest trapped or damaged cable within the backbox.
NB: With no load. there must be nothing plugged in to sockets, no just switched off at socket switch or appliance switch.
Double check all connections, if no joy. Then an insulation resistance test will be the next positive step, but it is not advised to IR USB sockets, so they will need linking out.

 

[PrenticeBoyofDerry]

I doubt you will have an IR (Insulation Resistance) tester.
Do you have any type of test equipment?
As you could test for dead shorts using a multi-meter.

If you do any electrical work it is advised to have some basic electrical test equipment.

How do you intend to test the RCD, once it can be energised?
It is a shame that you thought the RCD was faulty and returned it, other than checking your work and the system you where installing too.

 

[Taylortwocities]

Do any of the circuits or wiring in the garage extend outside (for lighting, external sockets, etc)?

Thats a good place to start. Without proper test equipment it is just going to be a process of elimination.

 

[JohnW2]

Hi, I changed some older sockets in the garage, and at the same time replaced the fused spur with an RCD Spur (13A 30mA) - the SafetySure one toolstation sell if it matters. ... The RCD spur trips immediately and doesn't stay on. I thought it was faulty and replaced it, but the replacement does the same. I have rechecked and the fused spur stay on.

A problem with something connected to the output of the 'RCD spur' would be the most likely/common explanation, but ....

We discussed here recently (and I did an experiment to confirm) that (although we don't understand how this is achieved) some makes of RCD sockets will not 'untrip' unless they have a satisfactory earth connection - so the same may well be true of some RCD FCUs ("RCD spurs").

To look into that possibility, assuming that there is an 'earth' connected to the 'RCD spur', you would need to check that it represented a 'satisfactory' connection to earth, but you may well not have the means of testing that.

Kind Regards, John

 

[skhudy]

A problem with something connected to the output of the 'RCD spur' would be the most likely/common explanation, but ....

We discussed here recently (and I did an experiment to confirm) that (although we don't understand how this is achieved) some makes of RCD sockets will not 'untrip' unless they have a satisfactory earth connection - so the same may well be true of some RCD FCUs ("RCD spurs").

To look into that possibility, assuming that there is an 'earth' connected to the 'RCD spur', you would need to check that it represented a 'satisfactory' connection to earth, but you may well not have the means of testing that.

Kind Regards, John

Thanks, if I just put on a standard socket and use a plug socket tester, will that tell me if is earthed satisfactorily? I've only got a multimeter

 

[skhudy]

Do any of the circuits or wiring in the garage extend outside (for lighting, external sockets, etc)?

Thats a good place to start. Without proper test equipment it is just going to be a process of elimination.

Thanks, nothing outside as far as I'm aware. I'm unsure if there's anything dangerous that needs to be fixed - is it safe keeping the standard fused spur which doesn't trip?

 

[skhudy]

I doubt you will have an IR (Insulation Resistance) tester.
Do you have any type of test equipment?
As you could test for dead shorts using a multi-meter.

If you do any electrical work it is advised to have some basic electrical test equipment.

How do you intend to test the RCD, once it can be energised?
It is a shame that you thought the RCD was faulty and returned it, other than checking your work and the system you where installing too.

just a standard multimeter. Is there any danger keeping the fused spur on? If so I may call a professional.

 

[JohnW2]

Thanks, if I just put on a standard socket and use a plug socket tester, will that tell me if is earthed satisfactorily? I've only got a multimeter

A plug-in socket tester will certainly tell you if there is no effective earth at all. Some of the more fancy/expensive plug-in testers would also give you a numerical indication of the quality of the earth connection ("loop impedance").

Kind Regards, John

 

[JohnW2]

Thanks, nothing outside as far as I'm aware. I'm unsure if there's anything dangerous that needs to be fixed - is it safe keeping the standard fused spur which doesn't trip?

I'm still not clear as to what is connected to teh output of this 'RCD spur'. Could you clarify?

Kind Regards, John

 

[skhudy]

I'm still not clear as to what is connected to teh output of this 'RCD spur'. Could you clarify?

Kind Regards, John

3 double plug sockets in the garage

 

[Taylortwocities]

OK

Its easy to narrow this down

Remove the wires from the load side of the RCD/spur. Does it still trip when turned on?
if yes there is a fundemental problem with the RCD/spur or how you have connected it.
if it doesn't trip, then remove the wires from all of the sockets and start replacing them, cable length and each socket at a time. Bit by bit, dont jump ahead of yourself.
(I guess the sockets are connected in series (ie one after the other, and not in a ring?)
Eventually you will find that you have added a socket, or a length of connecting cable that makes the RCD trip.
Then you'll be able to sort it out.\

NOTE:

1. this is not the best way to fault find.
2. make sure you turn the the power off at each stage when you are anywhere near wires that are, or may be, live.

 

[JohnW2]

Remove the wires from the load side of the RCD/spur. Does it still trip when turned on? ... if yes there is a fundemental problem with the RCD/spur or how you have connected it.

... or, as I have said, possibly an ineffective connection from a (correctly-connected) CPC to 'earth'.

Kind Regards, John