Adding a garage consumer unit

[Paddington]

hi, am newly qualified and need to do two circuits for registration process, so want to get this right. Main CU in garage is under sized for mcb's (only holds 6). So going to install additional garage consumer unit populated with 1 x 20a rcbo for 2.5mm radial circuit and 1x 6a rcbo for garage and external led lighting. Supply will be from a 32a mcb (this is rcd protected) which will be a sole supply as I will remove a soon to be redundant electric shower supply. I will be using 6mm t&e supply for the garage, all and any advice regarding testing for the additional CU (not the circuits). I am going to test it as though it were a new radial circuit, then obviously do a full test on the 20a and 6a circuits when I've completed those. Any helpful advice welcome.

 

[westward10]

So you are going to install a separate CU to off load some of the circuits from the main CU?? Would sound more sensible to up grade the main CU.

 

[Midwest]

Why not.......duuuuur, what he said ^^^^^^^^

 

[Paddington]

So you are going to install a separate CU to off load some of the circuits from the main CU?? Would sound more sensible to up grade the main CU.

Simplest way of getting 2 new circuits for inspection, relieve space on mainCU, segregate supply for working in garage / workshop from house. Get registration then upgrade CU to new 17th edition 10'way rcbo board. Garage electrics need sorting anyway so this kills many birds with one stone.

 

[Midwest]

Why bother doing it twice?

 

[Paddington]

Why bother doing it twice?

Oh and practice / confidence building, but good quality inspection circuits mainly.

 

[Midwest]

If you've the confidence to install two new circuits, you should have the confidence to replace the original CU. The tests are the same

 

[westward10]

The best way to show a job you have done is to test the place, replace the main CU and resolve any issues. Adding on a two way board will look ad hoc and you may well get asked about discrimination between protective devices which you will want to avoid.

 

[Midwest]

It would look ****.

 

[telectrix]

why fit a RCBO for garage sockets when there is already RCD protection in the main CU? If the CU is hi-integrity and the T/E cable to the sub is surface, then feed sub from a non-RCD way. better way is as said before. upgrade the main CU.

 

[Paddington]

The best way to show a job you have done is to test the place, replace the main CU and resolve any issues. Adding on a two way board will look ad hoc and you may well get asked about discrimination between protective devices which you will want to avoid.

Eventually want totally separate spark to outside / workshop garage, so when I do new main CU will split tails with henleys then have power in the event of main CU problem. Discrimination a good point though, hoping testing will show rcbo is faster than rcd, if not then all resolved with upgraded main CU as you said but this route the positives out way the negatives.

 

[Midwest]

If you installed a high integrity CU, you could achieve independent supply to the garage.

Why would an RCBO be faster than an RCD?

 

[westward10]

Why would an RCBO be faster than an RCD?[/QUOTE]
Doesn't weigh as much?

 

[westward10]

Eventually want totally separate spark to outside / workshop garage, so when I do new main CU will split tails with henleys then have power in the event of main CU problem. Discrimination a good point though, hoping testing will show rcbo is faster than rcd, if not then all resolved with upgraded main CU as you said but this route the positives out way the negatives.

Don't know what to say to that really.

 

[Midwest]

Haven't put someone else off have we. OP you seem suitably qualified, come back and discuss, there's a lot to learn from members here. Perhaps start at the beginning?

 

[Pete999]

So you are going to install a separate CU to off load some of the circuits from the main CU?? Would sound more sensible to up grade the main CU.

What he said

 

[Paddington]

Haven't put someone else off have we. OP you seem suitably qualified, come back and discuss, there's a lot to learn from members here. Perhaps start at the beginning?

As said recently qualified and need to do a wider variety of work to increase confidence and test a wider variety of circuits. This idea seemed to tick a number of boxes, as it's my own house I'm not bothered about some duplication of work. Stroma have told I need to install two new circuits, but not a consumer unit change,. I haven't the diversity on the current CU to give me those circuits and if the CU is upgraded then I can see that causing me wider issues during the inspection. I still can get flustered during exams and stuff like that, whereas to my mind, this isn't a CU upgrade it is managing external electrics, so would qualify as new circuits. Appreciate what everyone is saying about upgrading the CU and I will do that when registered. Apart from the thought that an easier way is main cu did the original design for the additional read ok? And any advice on testing it?

 

[westward10]

If you are going to be assessed you need to be competent with testing and the use of test equipment.

 

[Midwest]

I see what your saying if it's your house, so doing things twice doesn't matter.

However, I used a CU change in my first assessment. At the end of the day, the test procedure is the same, whether its two or twenty two circuits. I see you've done an inspection & testing course, so you just need to apply what you learnt on the course.

If you not confident at the moment, now's perhaps not the time to consider being assessed for scheme membership. Perhaps you should consider working for another sparks, to gain some more experience & confidence.

 

[DPG]

He didn't say he'd done an apprenticeship.

 

[Midwest]

Suns over the yardarm as well.

 

[Dave OCD]

Well I'd say it's perfectly normal to seek some more experienced advice and reassurance, going through an assessment process when you've only just qualified would feel quite daunting,suddenly you're on your own and thinking of all the things that you may be asked - and many with far more experience post on here pre-assessment seeking assistance.

 

[Spunkywads26]

Wow this thread has gone a long way to confirm my suspicions. I have been lurking around the forum for a while now and have been quite nervous about posting questions as it seems that the most active members have become tired of helping. It would seem that they have become very cynical and enjoy slagging off people and flexing their knowledge. I think that people need to remember that they were once somebody who were starting out with limited knowledge and little confidence.

So what if someone has 'changed career's' and done a 'short course' and considers themselves a spark. Its not their fault but that of the industry we are in.

I did an apprenticeship, i've won an award along the way and even been to university and got a BEng Hons in Building Services. I left the trade for 15 years and now starting back. I feel like the OP guy, that I have all my qualifications in place but lack the experience.

On the flip side, I have seen plenty of posts that demonstrate people asking questions which are easy to answer and show that the poster is low on knowledge. I do understand that this is annoying but advise people to step away if you feel that you are going to post a sarcastic, miserable reply.

In true form, now begins the sarcasm (which as long as it is good banter type i'm more than fine with)

 

[westward10]

Start joining in we welcome new input.

 

[Toneyz]

Surely you need to show more of an installation than this to deemed competent enough to belong to one of these self assessment schemes?.

 

[Octopus]

Why bother doing it twice?

And more importantly why would the client pay twice?

 

[Dave OCD]

He's doing the work in his own house.

And more importantly why would the client pay twice?

 

[Marvo]

Okay, I've removed some posts that ...let's say... weren't constructive and some other posts that were focussed on those.

Nobody is under any obligation to prove their competence to anyone else on the forum and likewise nobody is obligated to to assist where they feel it might not be appropriate.

Play the ball not the man, please don't make statements of your judgements about others.