Garage electrics from main house

[Neptune]

We have a garage attached to the property and are having it converted to an office with a small toilet. Electrics will include, internal lights, an external light, a few sockets and a extractor fan.

There is a cable coming into the garage currently from the house and is connected into the main consumer unit. It's a 2.5mm T&E cable wired into a 32amp MCB. It has RCD protection.

I think it would be okay to use the existing cable as a radial circuit for a few sockets and also have it initially split into a FCU (3amp Fuse) and have this running a lighting circuit? I would use 2.5mm cable for the sockets and 1.5mm cable for the lights. Would this be okay?
If yes, what would happen, if the load on the sockets was higher than intended? I assume it would trip the breaker in the house

Alternatively, what would be the advantages of using one of these?

Axiom Metal Garage/Workshop Consumer Unit 3 Way | Toolstation

BS 7671 IET Amendment 3. BS 61439-3. • 1 x 63A 30mA RCD • 3 x Type B MCB (1 x 32A, 1 X16A 1 x 6A) • Dimensions: (HxWxD) 185 x 145 x 110mm

www.toolstation.com

I could have the incoming cable going into this RCD and have a Ring for the sockets and a separate circuit for internal and one further for the external lights.

Can I please have your advice on the above. Thanks in advance.

 

[loz2754]

I don't agree that i should get a 'dislike' for giving advice.

I wouldn't worry too much about getting a dislike. I just got one on another thread for giving my opinion. From the same 'disliker', in fact.

I think the dislike button should be removed, as it only serves to provoke ill feeling.

People may by all means disagree, preferably backed up by a reason for such disagreement.

 

[UNG]

The forum has had these issues before.

And will continue to have the these problems after all electrics is only a few wires and there is nothing speciai in connecting them all up

We have a DIYers asking questions, so we are expected to assist in some way, without giving step by step instructions of course. If we don't guide in the right direction, then some of these DIYers may carry on regardless, causing danger to themselves and others.

Guidance = get an electrician in to advise and install in the safest way possible

It seems to be a default answer to “get an electrician” on a DIY question, so forgive us. We don’t know your competency level, although you have said some of the right things…

IMO this isn't guidance it's carry on regardless

We can advise.... We can state the safety implications.... We can take a guess at the type of person asking the question, and of course, if we think the job is beyond a particular persons ability, then we can say so.
But as mentioned... they may carry on regardless. That is their prerogative (and their fault if anything goes wrong) after being given advice.

Sometimes it is best to not reply with any advice no matter how limited it is, then you cannot be implicated if an incident occurs

I don't agree that i should get a 'dislike' for giving advice.

I gave you my reason in the post prior to yours but you appear to be playing the devils advocate

I think the dislike button should be removed, as it only serves to provoke ill feeling.

How woke. Maybe all the buttons should be removed so as not to cause offence anyone by someones choice

People may by all means disagree, preferably backed up by a reason for such disagreement.

We have a disagree button I chose not to use it and if I do I give a reason

 

[Neptune]

I've cancelled the plans for a shower. Thanks for informing me of the additional regs on that.
I can also see we are getting into the spiral of "get a electrician", "but I can do this", "no you can't, get an electrician"...

As a DIY'er who has been involved in many electrical projects and takes safety very seriously, I do find this frustrating. I know I can do this with some guidance from you. It's your experience that draws us to these forums rather than finding this information in piecemeal across the web.

I do have a couple of questions I would like your advice on please.

1. The garage consumer unit seems to be designed for surface mounted cables. This is not the case in my office as the cables will be under the plasterboard. The unit only has top and bottom entry. Is it a case of sinking the unit into the wall deep enough so the cable entry is below the plasterboard?

2. In my situation, can I use the 20mm knockouts with the socket grommets used for metal boxes? I can then use the fire intumescent sealant to close the gap after the cables have been fed through.

3. I need to join the incoming cable (from house) to a longer length as it wont reach the office consumer unit in its current state. I have sunk a 1 gang box in the wall and will make the join here and use a blanking plate once finished. I am planning to use a 10mm cable from this box/join to the consumer unit. Again, provide future proofing. In the future I can change the incoming cable to this join and everything downstream should be decent enough.
How do I join the 2.5mm cable and 10mm cable within this 1 gang box? I normally use wagos...

Thanks for your support

 

[westward10]

From your past threads you have had plenty of guidance for your 'electrical projects' but the forum will draw a line at giving step by step advice even though this has been the case with some of these. You take safety very seriously but having a rudimentary knowledge of the works will hinder your take on this because without truly understanding the principles electrical safety it is doubtful you can employ them. All the questions you ask in #18 and previous posts suggest you should not be undertaking these works and there is also the question of notification to Building Control under Part P of the Building Regulations.

 

[Neptune]

All the questions you ask in #18 and previous posts suggest you should not be undertaking these works

Which question in post #18 is concerning you?

 

[westward10]

Which question in post #18 is concerning you?

All of them.

 

[Neptune]

All of them.

OK...
Let's go through the first one on the "garage consumer unit" not having back entry for cables and asking whether people sink some of it in the plasterboard to hide the incoming cables on top and bottom.

Why is that a shocking question?

 

[westward10]

OK...
Let's go through the first one on the "garage consumer unit" not having back entry for cables and asking whether people sink some of it in the plasterboard to hide the incoming cables on top and bottom.

Why is that a shocking question?

I am not going to entertain you with an answer.

 

[buzzlightyear]

Case closed what the man's says above , I mentioned this in post #2.

 

[DPG]

OK...
Let's go through the first one on the "garage consumer unit" not having back entry for cables and asking whether people sink some of it in the plasterboard to hide the incoming cables on top and bottom.

Why is that a shocking question?

I'm someone who is all for people doing their own things within their comfort zone and ability. Electrics, car repairs, plumbing, whatever. However, I think you do need to get an electrician in for this one. Some of the things you are asking (eg. how to join 2 cables of differing sizes, and how to get cables into the CU) show that you lack some key knowledge to complete this job. And that's before we get on to doing the necessary testing.

There's no shame in knowing your limits. You seem more capable than most DIYers and you should be proud of that.

It's like car repairs - I can do the basics such as servicing, brake replacement etc. but anything beyond that goes to the mechanic so I know it gets done safely.

 

[littlespark]

I'm someone who is all for people doing their own things within their comfort zone and ability. Electrics, car repairs, plumbing, whatever. However, I think you do need to get an electrician in for this one. Some of the things you are asking (eg. how to join 2 cables of differing sizes, and how to get cables into the CU) show that you lack some key knowledge to complete this job. And that's before we get on to doing the necessary testing.

There's no shame in knowing your limits. You seem more capable than most DIYers and you should be proud of that.

It's like car repairs - I can do the basics such as servicing, brake replacement etc. but anything beyond that goes to the mechanic so I know it gets done safely.

Agree with this, but need to question the bottom paragraph.

I would say brake replacement should be done by a mechanic. How would your insurance fare if you crashed because your car didn’t stop when it should have…. Because you replaced the brakes yourself.

Personal experience. One of my first cars, my dad changed the pads… They worked fine, but didn’t release. Had to change them again 3 months later because it was braking all the time.

Could also argue that anyone shouldn’t be responsible for changing a wheel, as it might fall off at speed if not done properly.


Im guilty of it myself, instantly telling someone to get a professional in… sometimes it is the best advice when the OP asks something completely out of order….
This thread started off ok, but the mention of joining onto 10.00mm is unnecessary.

A couple of years ago, @Dan the forum boss posted guidance on how to help DIY, which I alluded to by saying DIYers would do the work anyway, with or without our help.

 

[DPG]

Agree with this, but need to question the bottom paragraph.

I would say brake replacement should be done by a mechanic. How would your insurance fare if you crashed because your car didn’t stop when it should have…. Because you replaced the brakes yourself.

Personal experience. One of my first cars, my dad changed the pads… They worked fine, but didn’t release. Had to change them again 3 months later because it was braking all the time.

Could also argue that anyone shouldn’t be responsible for changing a wheel, as it might fall off at speed if not done properly.


Im guilty of it myself, instantly telling someone to get a professional in… sometimes it is the best advice when the OP asks something completely out of order….
This thread started off ok, but the mention of joining onto 10.00mm is unnecessary.

A couple of years ago, @Dan the forum boss posted guidance on how to help DIY, which I alluded to by saying DIYers would do the work anyway, with or without our help.

Brake replacement is well within the scope of a decent home mechanic - there is nothing particularly complex about changing brake pads or even discs. But again, it relies on being in your comfort zone and understanding what needs to be done. I know a couple of people who replace springs and shock absorbers, and I know they are capable of doing this safely. Personally I'm not comfortable doing this so I would get it done by someone else.

 

[Neptune]

In case someone else wants to come along and provide some advice but also to clear this up. The question on joining 10mm cable had some context. Its there to provide future proofing as any future armoured cable from the house can connect to this.
The proposed join is an accessible join which I assume does not need to be maintenance free and I also mentioned that I’ve used wagos in the past. I’m not aware that wago do a suitable product for this situation.

I was looking for some validation and clarity around this.

 

[littlespark]

10mm is big enough for an electric shower or cooker… overkill for a handful of sockets and lights…

 

[Neptune]

10mm is big enough for an electric shower or cooker… overkill for a handful of sockets and lights…

If in the future, if we wanted additional draw, it will provide scope for that. I appreciate its well over spec’d for todays requirements.

It’s difficult to explain but if we wanted to upgrade the existing 2.5mm supply cable in the future, it could come and connect in this box and everything downstream is setup for higher loads e.g. 10mm to CU, RFC on 32 amp using 2.5mm cables, etc. There will be no need to rip up the plasterboard. That was my rationale.