Get the electrician to megger the circuit while they are there - this will hopefully pick up any cable faults.

wow, I have this exact problem!

House is 12-15y old, the switchboard has RCD thingies in it which often trip, guaranteed when we are away, and takes out the freezer, the garage doors, my pis and a windows server, and the electric gate.

We have lost a lot of food this way.

Himself is always blaming my pc gear, but maybe its the freezer!

So far I mitigate this by using a UPS on the pc gear and get the UPS software to email me when it detects an outage.

kiwifidget:

 

wow, I have this exact problem!

 

House is 12-15y old, the switchboard has RCD thingies in it which often trip, guaranteed when we are away, and takes out the freezer, the garage doors, my pis and a windows server, and the electric gate.

 

We have lost a lot of food this way.

 

Himself is always blaming my pc gear, but maybe its the freezer!

 

So far I mitigate this by using a UPS on the pc gear and get the UPS software to email me when it detects an outage.

 

 

 

it may not be just 1 thing causing the problem, it's could be several items, it could be a small earth leakage in the defrost element (not enough on it's own) that is enough to trip the RCD.

or it could be a faulty RCD, or it could be faulty wiring, with out getting it checked out there is no way to see for sure, don't take for granted that just because someone else has a similar problem that the solution for you will be the same.

kiwifidget:

 

wow, I have this exact problem!

 

House is 12-15y old, the switchboard has RCD thingies in it which often trip, guaranteed when we are away, and takes out the freezer, the garage doors, my pis and a windows server, and the electric gate.

 

We have lost a lot of food this way.

 

Himself is always blaming my pc gear, but maybe its the freezer!

 

So far I mitigate this by using a UPS on the pc gear and get the UPS software to email me when it detects an outage.

 

Do you have any surge protetors downstream of the RCD? That's what has caused a lot of the problems I have had, since they have a MOV to the earth from live and one from neutral, when those conduct on a small transient it can be enough to push the RCD into tripping.

Faults like this can be very hard to find.

One in particular I was called to had three previous electricians try to fix to no avail.

After about two hours of testing, tracing wires, pulling circuits apart and retesting we found a junction box under the house that had melted and was moist.

Being that it was an intermittent fault and it metered out OK half the time and badly the other half it was a right bastard to find.

We got it in the end though so customer was happy.

Faulty appliances that involve water are the usual suspects, dishwasher, washing machine, wastemaster and also fridges and freezers.

But also ants, rats/mice, leaky homes, old wiring, RCDs downstream of RCDs and even inductance on long cable runs can cause problems. 

30mA has decent headroom for inductance, 10mA for schools can be a nightmare.

My neighbour had a new circuit board with RCBOs (combined RCD/breakers) - one of which kept tripping.  The RCBO was borked.  My son (sparky) took a quick look before calling the electrician who installed it back.  The RCD function was good / tested fine, but the breaker would consistently trip with a load of ~ 1/2 amp or so. 

gzt: What is left on the problem circuit. If you unplug everything on that circuit does it still trip?

Yes, with nothing at all on this RCD-controlled circuit.  However, some stuff on another different RCD-controlled set of outlets that comes off the same contact breaker (only discovered this today when I went ant/animal hunting behind the outlets).  No livestock, all connections tight.

richms:

 

kiwifidget:

 

wow, I have this exact problem!

 

House is 12-15y old, the switchboard has RCD thingies in it which often trip, guaranteed when we are away, and takes out the freezer, the garage doors, my pis and a windows server, and the electric gate.

 

We have lost a lot of food this way.

 

Himself is always blaming my pc gear, but maybe its the freezer!

 

So far I mitigate this by using a UPS on the pc gear and get the UPS software to email me when it detects an outage.

 

 

Do you have any surge protetors downstream of the RCD? That's what has caused a lot of the problems I have had, since they have a MOV to the earth from live and one from neutral, when those conduct on a small transient it can be enough to push the RCD into tripping.

 

 

 

No surge protectors, nothing at all

I have now traced out the whole circuit that I'm having problems with:

RCD B is the one I am having trouble with, which used to run just the fridge.  Now it is running off RCD A perfectly.  However, Outlet A went to a distribution box (Kambrook, says 86 on it, and that just might be the year I bought it).  I removed this outlet box, and lo! RCD (not now connected to anything) has not popped off for the last 3 days.

Could a problem with this outlet box lead to an RCD popping on a later part of the circuit?  I presume so, and this is what appears to be happening.

If so, the whole circuit is rather a botch-up, isn't it?

In theory that shouldn't happen, but it's not exactly unheard of.

mdav056:

 

I have now traced out the whole circuit that I'm having problems with:

 

 

RCD B is the one I am having trouble with, which used to run just the fridge.  Now it is running off RCD A perfectly.  However, Outlet A went to a distribution box (Kambrook, says 86 on it, and that just might be the year I bought it).  I removed this outlet box, and lo! RCD (not now connected to anything) has not popped off for the last 3 days.

 

Could a problem with this outlet box lead to an RCD popping on a later part of the circuit?  I presume so, and this is what appears to be happening.

 

If so, the whole circuit is rather a botch-up, isn't it?

 

Does this kambrook  "box" have built in surge protection? if so then it is a very likely offender

gregmcc:

 

mdav056:

 

I have now traced out the whole circuit that I'm having problems with:

 

 

RCD B is the one I am having trouble with, which used to run just the fridge.  Now it is running off RCD A perfectly.  However, Outlet A went to a distribution box (Kambrook, says 86 on it, and that just might be the year I bought it).  I removed this outlet box, and lo! RCD (not now connected to anything) has not popped off for the last 3 days.

 

Could a problem with this outlet box lead to an RCD popping on a later part of the circuit?  I presume so, and this is what appears to be happening.

 

If so, the whole circuit is rather a botch-up, isn't it?

 

 

 

 

Does this kambrook  "box" have built in surge protection? if so then it is a very likely offender

 

No, it doesn't.