Replace MCB with RCBO's

[Licklieder]

Hi Guys.

I’ve got a 12 way Volex 17th Edition split consumer unit that currently has 4 MCB no RCD (for electrical heating) and 5 MCB with RCD protection for lights, immersion, Oven / Hob, Final Ring, & radial socket.

There’s a guy on ebay selling New Old stock Volex RCBOS’ of the right type (RCBO function AC & pulsing DC, MCB function – Type B: https://bit.ly/2PRx1m6 ) & ratings, so I was considering replacing the current set of MCB’ with RCBO’s.

I have a Fluke 1653B multifunction tester so would perform continuity, IR and trip time / current testing before and after the replacement, and will source a torque screwdriver to ensure everything is done up correctly.

Is there anything else I should be considering ? Aside from updating the labeling when done.

M.

 

[blup]

I think the type AC doesn't have the dc pulsing function.

Blup

 

[AndyPRK]

That brand are type A rcd for DC.

Often ppl don’t like Rcd for heating, as you can get false trips.

 

[JohnW2]

Often ppl don’t like Rcd for heating, as you can get false trips.

What sort of 'heating', and why (why the 'false trips')?

Kind Regards, John

 

[AndyPRK]

Storage heaters. And water absorbation

 

[JohnW2]

Storage heaters. And water absorbation

Interesting. I wasn't aware of that.

Kind Regards, John

 

[EFLImpudence]

Storage heater elements are not earthed, are they?

 

[JohnD]

I think they are.

Can't be bothered to go and look at one, though.

They have a metal sheathing. If the element were to be damaged or burn through, it could become live.

 

[EFLImpudence]

I think they are.

That's good enough.

Can't be bothered to go and look at one, though.

Maybe you should.
https://www.google.com/search?q=storage+heater+elements'&sxsrf=ALeKk00iIA9QmD8vHR0rAd04QtWpm-sFAQ:1620144458285&source=lnms&tbm=isch&sa=X&ved=2ahUKEwinxq63tLDwAhXOgVwKHRD_CYwQ_AUoAXoECAEQAw&biw=1559&bih=761

They have a metal sheathing. If the element were to be damaged or burn through, it could become live.

They are inside the bricks.
MCB?

 

[Licklieder]

That brand are type A rcd for DC.

Often ppl don’t like Rcd for heating, as you can get false trips.

it's hard to make out from the photos on ebay, but when i zoom in, they do look like type A to me:

 

[Licklieder]

I'll bear in mind the possibility for nuisance tripping on heating circuits and keep hold of the exsting MCB's just in case. At the moment, i have cheapo convection heaters fitted but intend to replace them with some nicer electric - wet style heaters in due course. Guess that explains why the spark who fitted my consumer unit way back when split those circuits off from the RCD.

That said, I have come across some manufacturers of radiator elements who specify the use RCBO's.

 

[JohnW2]

it's hard to make out from the photos on ebay, but when i zoom in, they do look like type A to me:

Indeed, I don't think there is any doubt (and that would correspond with the description to OP posted) ...

Kind Regards, John

 

[AndyPRK]

How do you turn the heaters on and off ?

is there a central timer ?

 

[crystal ball]

Storage heater elements are not earthed, are they?

Correct they sit inside the bricks, no contact with earth

 

[Licklieder]

How do you turn the heaters on and off ?

is there a central timer ?

As per the original late 60's / early 70's install Each room has it's own thermostat. There used to be a central timer / relay box but i too that out when i replaced the old mechanical thermostats with Aube Th132's digital onse which work well for temp control / disabling the heaters with the 'holiday' function. Each heater is connected to the circuit via it's own FCU.

A project for another day will be to add appropriate isolation switches before the thermostats as the installation pre-dates that requirement.