Old black box near consumer unit

[h4r00n]

Hi, My electrics keep tripping.. this black box in the picture seems to be the culprit. Slight touch of it and it trips. The electrician suggested removing this and connecting two main cables from main switch to the consumer unit with connectors. He said this black box is very old and not needed. Plus it looked melted in the inside. Is this OK to do?

 

[Avo Mk8]

Heres what he did after i told him no thank you and to replace isolator red switch with rcd and see if still trips which it did

Well done for insisting that the rcd should not be replaced with a switch. You did the right thing!
The next step is to find out what is causing the tripping, as per previous predictions!!
That is something I would have expected your "electrician" to have done already!

 

[Lucien Nunes]

Yes your next quest is to discover whether the tripping is caused by a specific fault, which could be equally be in an appliance as in the house wiring, or whether it's simply a result of the total normal leakage in the house being close to the tripping threshold of the sole RCD supplying it.

Did the old switchfuse get saved by any chance?

 

[James]

With suggestions like replacing rcd with main switch etc, I would recommend getting a new electrician (one that knows what he / she is doing)

 

[h4r00n]

Yes still have the old black isolator.. stuck on wall. Will take it down and send.. PM me address.

Issue still persists.. even switched all mcbs down other than just upstairs and downstairs lights and it tripped RCD after around 30 mins with lights not switched on. Any power on any sockets trips the RCD. The RCD is 80amp covering all MCBs it thats worth noting. Maybe some earth leakage somewhere?

Also wanted to ask... have old dishwasher and cooker hob still plugged in. Very difficult to get to as I believe its on an extension lead hidden behind kitchen counter. I did manage to just switch the plug switches off by removing Oven and reaching around. It still tripped. Just thought that the fact that the RCD still trips with all MCBs down and just 2 light MCBs up might mean theres no point ripping out kitchen counter?

Bit annoying because dont want to spend too much sorting it out as in a couple months we have builders in for an extension which includes full rewire.

 

[James]

It sounds like you might have a fault on a circuit between N and earth.
unfortunatley if it is in one of the appliances like the hob or dishwasher, switching the socket off will not remove the fault.
it can still cause problems even when the mcb is switched off.

most likely suspects to are
outside lights
immersion heater
oven or grill
electric hob
fridge freezers
anything with a heater element in it.

 

[Lucien Nunes]

Have you noticed a tendency for the RCD to trip when heavy loads are used e.g. (heating / cooking equipment, or when large power tool motors start up? That would tend to confirm the theory of a neutral-earth short because the load creates voltage drop in the neutral which drives current through the fault to earth.

Thanks re saving switchfuse, will send PM

 

[h4r00n]

Yes, switching on fridge or freezer, microwave, kettle, hair dryer trips RCD for any plug in house. Having boiler on doesnt until maybe 10 mins in, same for phone charger and lights. Having everything switched off inc all plugs and lights also trips RCD after around 20 mins.. sometimes maybe 2 hours at most.

Will call another electrician to pop down. Thanks for all the help. I was hoping it was just the old uneccasry insulator switch which causes the issue as any nudge of it and it tripped.. but thats been bypassed and issue persists.

 

[nicebutdim]

Would also be interesting to know what level of current trips the existing RCD. Unfortunate that your electrician didn't conduct this basic test.

 

[h4r00n]

Just an update.. seems to be working. Missus said she was vacuuming when it tripped. She also mentioned she 'thinks' the plug pulled out too when vacuuming. Anyhow, I just opened the socket, checked connections and wiring it all seemed fine. Took out the 3 earths including the earth for the metal back box, looked ok. Connected it all backup and now weirdly electrics all seem fine.

 

[h4r00n]

There is a slight little kink in the neutral wire as shown in pic above but just put it all back together and electrics have been on for an hour now.. hopefully its sorted.

 

[snowhead]

Check on the reverse side of the black wire where I've marked it,, with the power off of course.
It looks like it's been trapped by the socket against the back box.