Adding a 2 way unit to a garage

[Mfctitch]

Evening everyone

I have been asked to price to add some more sockets and lights to a garage plus a few out side sockets.
now the garage already had a supply from the house via SWA cabling which just feeds a socket and the lights via a fused switched spur.
now the consumer unit in the house is an old "Ashley & Rock" with Supasafe MCB's. with blue writing if that helps the whole lot is protected with one main RCD.

Now for my question.
I know that I can fit just a 2 way unit but I was thinking that with more sockets and some of them outside it would be better to fit an RCD in the garage.
but I need this to trip before the house RCD trips so any suggestions would be great.

Thanks for all suggestions

 

[Octopus]

I'm not sure where you got the idea that I did not know?

Yes I did know that part of the problem.

What I don't know and there has not been an answer that people who have probably forgotten more than I know all agree on. Is what is the best way to protect the circuits in the garage while stopping the house RCD tripping.

May be you should review your posts before posting them.

To stop the house tripping it needs to be "fed" from a non protected MCB or a time delayed RCD - surely you know this......

grrrrrrrrrrrrrrrrrrrrrrrrrr

 

[Mfctitch]

Ha ha
This is getting silly but in the hope of getting something of of this I'll play.

The consumer unit in the house is a very old unit and only has one main RCD.

I do believe that a time delayed RCD was mentioned but I'm sure someone shot that Idea down.

But feel free to correct me yet again.

 

[Octopus]

Ha ha
This is getting silly but in the hope of getting something of of this I'll play.

The consumer unit in the house is a very old unit and only has one main RCD.

I do believe that a time delayed RCD was mentioned but I'm sure someone shot that Idea down.

But feel free to correct me yet again.

OK matey lets play it your way.

WHAT DO YOU PLAN TO DO?

 

[Mfctitch]

To be honest at the moment my options are to:

Just fit a standard 2 way unit fit the sockets and lights text sign off and get paid.
or
carry on here looking for and answer and failing that do some more research in the hope of finding a way to do the job so that the house does not trip.

Bearing in mind that at the end of the day when I give the customer the two costings if the right way turns out too expensive he might just go for the cheaper option.

But that's life and at least I will have learnt something.

 

[GLENNSPARK]

Hi, Im sure if you put a standard 30mA 40ms rcd in the garage consumer unit then this will switch before the rcd in main house consumer unit. So hence the main power to the whole house will be unaffected.

twaddle....
think `accumilated earth leakage`...

 

[eganelectrical]

Ok well I was told that an 'additional" rod will help and good practice. I did t mean the rod as the sole earth protection in the garage.

Just to get my head round this Murdoch, I only got arsy because of your arsy comment!

Anyway more to the topic.. I have seen 16th edition boards put in where the upfront rcd has been changed to time delay so the one on the ccu trips before the one up front. Why can't this be done the same way for the garage ccu? Change the house to time delay and the garage one will trip first??

 

[GLENNSPARK]

Ok well I was told that an 'additional" rod will help and good practice. I did t mean the rod as the sole earth protection in the garage.

Just to get my head round this Murdoch, I only got arsy because of your arsy comment!

Anyway more to the topic.. I have seen 16th edition boards put in where the upfront rcd has been changed to time delay so the one on the ccu trips before the one up front. Why can't this be done the same way for the garage ccu? Change the house to time delay and the garage one will trip first??

OK for the garage sub....not OK for the house finals....
Keep the house finals on 30mA for fault (TT)....stick a 100mA s type in for the garage feed....30mA in the garage board....

 

[eganelectrical]

Ok now I'm confused! Which one will be the time delayed??

 

[Mfctitch]

OK for the garage sub....not OK for the house finals....
Keep the house finals on 30mA for fault (TT)....stick a 100mA s type in for the garage feed....30mA in the garage board....

Dont mean to awkward but no space in the old consumer unit and even if there was space not sure I could get one to fit.
But thanks again.

 

[eganelectrical]

What about splitting the tails at the house ccu and adding additional unit (non rcd protected) to feed garage swa. Then adding 30mA to garage unit??? Suggestions please??

 

[GLENNSPARK]

Dont mean to awkward but no space in the old consumer unit and even if there was space not sure I could get one to fit.
But thanks again.

stand alone and a henley should see to that...

- - - Updated - - -

Ok now I'm confused! Which one will be the time delayed??

time delayed top end....

- - - Updated - - -

What about splitting the tails at the house ccu and adding additional unit (non rcd protected) to feed garage swa. Then adding 30mA to garage unit??? Suggestions please??

depends on the earthing arrangements..

 

[Mfctitch]

Thanks but why do I see to keep finding fault with people helpful suggestions.
The consumer unit is boxed in with no room to get at anything without causing damage.
Sorry

 

[GLENNSPARK]

Thanks but why do I see to keep finding fault with people helpful suggestions.
The consumer unit is boxed in with no room to get at anything without causing damage.
Sorry

can you not find a space in either an adjacent cupboard or maybe the cupboard above (if there is one) to mount a stand alone enclosure?

 

[Engineer54]

The OP has been asked on several posts now as to ''What'' is the earthing system on this installation, but seems reluctant to tell us!!

 

[Mfctitch]

I will try and get back to the house before the weekend and take some photos of the problem.
Plus I will also check the earthing arrangements
as see if the SWA goes into the consumer unit.