Earth to garage?

[JohnD]

very simple job. You need a 30mA RCD (the most common type) rated to carry a current equal to or greater than the fusing of the circuit (they are usually rated at 80A or 100A so almost any will do).

(there are also available 100mA RCDs, and time delayed RCDs. These are more expensive, less common, and not what you need)

Once the RCD is fitted, it will start to trip if there is any earth leakage on the garage circuits. if this happens you will need investigation and rectification of the faults and may lead you consider having it rewired.

 

[p4ult]

Cool I will give that a go,

Thanks again John and Dan for your help

Paul

 

[p4ult]

Hi again,

Is this the right RCD, it says 30mA but only 13amps is this right? All the ones I an looking at on the net only seem to be 13amps

http://www.fwb.co.uk/mall/productpage.cfm?store=FWBGroup&productid=EAT493

 

[JohnD]

I supose you could use one of those, but I was actually thinking of one of these

http://www.screwfix.com/prods/77076...its/Wylex-MCBs-Incomers/Wylex-80A-30mA-DP-RCD

http://www.screwfix.com/prods/32311...Consumer-Units/Wylex-IP40-Insulated-Enclosure

It is likely that the cable supplying your garage is capable of carrying more, so it would be a pity to limit it with a 13A fuse cartridge.

I am not familiar enough with MICC to know what the capacity is.

If you were to have the old fusebox in the garage replaced, most people woud use something like this
http://www.screwfix.com/prods/73324...er-Units/Wylex-Garage-Unit-2-Way-63A-30mA-RCD
so the RCD is in the garage, and more convenient to reset if it trips while you are working in there.

 

[333rocky333]

From what i have read i would say no

It seems to me you want a modular type rcd which usually goes on a dinrail

This will fit inside an enclosure, they look SIMILAR to a mcb but are twice the width,

As your mcb i think is 16 Amp , I would say one of 20 amp or more

The rcd if fitted in the garage would not protect the cable from the house though

Or am I getting mixed up

OR as johnd says

 

[RF Lighting]

Pyro is a ?trade? name for that fire-resisting copper-sheathed cable.

It is an abbreviation of Pyrotenax, a brand name for MICC manufactured by BICC (British insulated calender's cables ltd.) It is like the vacuum cleaner being referred to as a hoover scenario.

Excellent stuff.

That installation looks to have been do to a VERY high standard.

It would be difficult to work on these days, as the glands and pot seals have imperial threads. It is virtually impossible to source these, as everything stocked / available is metric.


It is hard to tell what size the supply to the garage is, but if I were a betting man, I'd say it's an imperial equivalant of 2L2.5 (2 core, light duty, 2.5mm² conductors)

According to my book, if installed to reference method 1, it is good for 31 amps.

 

[p4ult]

Cool thanks

 

[333rocky333]

That installation looks to have been do to a VERY high standard.

Except the earth link to the sockets, it would have been green them days

The sockets have earth terms, so it was not too old for that they should have fitted the mk earth posts in the back box before they fitted them.
That was pre 14th regs and still applys

 

[RF Lighting]

It was normal practice not to bother fitting an earth link from the back box to the socket front back in t'day

 

[333rocky333]

So what was the earth terminal on the socket for?

 

[p4ult]

Hi guys,

I need some more help im affraid, I have brought an RCD like in the link John posted. Before fitting I have one more question.
I opened the box as shown in the pic below to have a look. The cable coming out of the bottom has an earth cable attached the the inside of the box which goes to the CU. The RCD which I will be placing in between the box ad CU has no earth terminal so where do i connect the earth wire?

Thanks again
Paul

 

[JohnD]

A modern RCD does not require an earth wire.

edited

just bypass the RCD and run an earthwire direct from the CU to the switchfuse.

edited again

Is there a parking terminal for earthwires in the RCD enclosure?

 

[p4ult]

Thanks again John

just bypass the RCD and run an earthwire direct from the CU to the switchfuse I was thinking of doing this

Is there a parking terminal for earthwires in the RCD enclosure? No

 

[ban-all-sheds]

According to my book, if installed to reference method 1, it is good for 31 amps.

27.9A according to mine. (They don't look PVC covered to me.... )

 

[RF Lighting]

Which table are you looking at?

According to table 4G1A in the 17th ed. 2L2.5 MICC is rated to 31A clipped direct (now ref method 'C')