I have a very strange repeated RCD tripping scenario, which appears to suggest that two unrelated circuits are connected. Any problem solving thoughts would be appreciated.
I have an electrician who has done several jobs for us (new lighting circuits, appliance installation, outside lights, changing sockets etc). I am very pleased with him, and he has visited around 5-10 times over the last year to try and fix this - but admits he doesnt understand it. He is going to bring in colleagues who specialise in troubleshooting. So we both just thought it might help to put the problem out there for any ideas. I do not touch anything electrical myself.
New build detached house, finished 2012. Dual split load consumer unit with RCD on both (picture). Everything worked fine until last summer when Air COnditioning installed by very experienced professional firm. They installed 5 split units in 5 rooms, and put two outside Mitsubishi units each with new dedicated supply with MCB in CU in two spare slots.
Ever since then we have had intermittent RCD tripping, which my electrician has investigated extensively. Coincidentally we have also replaced all appliances since then with new Miele ones and new Liebherr high end fridge, so unlikely they would be involved.
More recently the RCD repeatedly trips unless the MCB for one of the air con circuits is switched off . Both the electrician and air con company have investigated this - but cannot find a fault with the air con circuit. However my electrician when checking all the possibilities discovered a very strange anomaly. First there is a 6 gang double pole grid switch in the kitchen for isolating various appliances (picture). He found that one of them (for plate warmer) had incorrectly had a simple (light) switch installed - so live and neutral were connected when on. He replaced that and checked all the others.
He then made a discovery which is hard to understand. The RCD immediately and repeatedly trips when the air con MCB is switched on. However it does not trip when air con MCB is on but dishwasher grid switch is off. Turning the dishwasher grid switch on immediately trips the RCD. The air con works fine and no RCD trip when dishwasher isolated, but dishwasher works fine and no RCD trip when air con isolated! We have repeatedly tested and found the same results.
My electrician is seeking advice but does not understand how a new air con supply can somehow be linked to the dishwasher which comes off the ground floor ring mains which has no connection to the air con circuits. Not only has he inspected and tested the CU several times but so have two very senior technicians from the air con company.
This all happens consistently including when all other appliances switched off, so I do not believe the supply is insufficient.
Hope this makes sense. I am not sure if posting pictures is allowed from new members, so I will try to do so in the next post.
I have an electrician who has done several jobs for us (new lighting circuits, appliance installation, outside lights, changing sockets etc). I am very pleased with him, and he has visited around 5-10 times over the last year to try and fix this - but admits he doesnt understand it. He is going to bring in colleagues who specialise in troubleshooting. So we both just thought it might help to put the problem out there for any ideas. I do not touch anything electrical myself.
New build detached house, finished 2012. Dual split load consumer unit with RCD on both (picture). Everything worked fine until last summer when Air COnditioning installed by very experienced professional firm. They installed 5 split units in 5 rooms, and put two outside Mitsubishi units each with new dedicated supply with MCB in CU in two spare slots.
Ever since then we have had intermittent RCD tripping, which my electrician has investigated extensively. Coincidentally we have also replaced all appliances since then with new Miele ones and new Liebherr high end fridge, so unlikely they would be involved.
More recently the RCD repeatedly trips unless the MCB for one of the air con circuits is switched off . Both the electrician and air con company have investigated this - but cannot find a fault with the air con circuit. However my electrician when checking all the possibilities discovered a very strange anomaly. First there is a 6 gang double pole grid switch in the kitchen for isolating various appliances (picture). He found that one of them (for plate warmer) had incorrectly had a simple (light) switch installed - so live and neutral were connected when on. He replaced that and checked all the others.
He then made a discovery which is hard to understand. The RCD immediately and repeatedly trips when the air con MCB is switched on. However it does not trip when air con MCB is on but dishwasher grid switch is off. Turning the dishwasher grid switch on immediately trips the RCD. The air con works fine and no RCD trip when dishwasher isolated, but dishwasher works fine and no RCD trip when air con isolated! We have repeatedly tested and found the same results.
My electrician is seeking advice but does not understand how a new air con supply can somehow be linked to the dishwasher which comes off the ground floor ring mains which has no connection to the air con circuits. Not only has he inspected and tested the CU several times but so have two very senior technicians from the air con company.
This all happens consistently including when all other appliances switched off, so I do not believe the supply is insufficient.
Hope this makes sense. I am not sure if posting pictures is allowed from new members, so I will try to do so in the next post.
