Garage electrics

Hi

I am going to install power into my detached garage. I do have C and G 2330 including level 3 so am competant but still not sure on a couple of things.

I live in a flat and the consumer is only 4 way with no spare way. The garage run all in is about 30m. I am going to use 4mm black external rubber flex using catenary wire.

1st query is - as the board is full and without upgrading to a bigger board....I will need to run 10mm tails from the main terminal after the meter to some sort of separate protection, ie RCD, and then out of this with the 4mm to the garage CU? Is that correct?

2nd query is - I've read on here that I may need an earthing rod, but which type of earthing system does this apply to?

Thanks

So your design is running a 4mm external rubber cable 30metres on a catenary wire. Can we assume your talking about Hi-Tuf or equiv.

You have obviously worked out that a 30m run of 4mm is not going to give you much to play with, load wise, after you take volt drop into account. I'm not going to do the calcs for you as your 2330 level 3 but suffice to say you ain't going to get a lot. If it's just one socket you might just be ok perhaps 2, though a CU might be a bit ambitious

Now I've had to get my lad to get me a coffee here, C & G 2330 level 3 ............you don't know the earthing arrangements in UK systems. That is a TT system

You also know that this work is notifiable under Part P ?

JONBOY28 said:

Hi

I am going to install power into my detached garage. I do have C and G 2330 including level 3 so am competent but still not sure on a couple of things.

Click to expand...

So you plan to pay the LABC fee and provide test results ?

JONBOY28 said:

I live in a flat and the consumer is only 4 way with no spare way. The garage run all in is about 30m. I am going to use 4mm black external rubber flex using catenary wire.

Click to expand...

Catenary if over any land other than yours requires permission via a wayleave.
What load max are you expecting at the garage ?
When you say rubber sheathed exactly what cable do you intend to use ?

As a minimum a poly sheath or (maybe) hi tuf, catenary cable needs to be very resilient to weather, weight stress and rubber isn't suitable.

JONBOY28 said:

1st query is - as the board is full and without upgrading to a bigger board....I will need to run 10mm tails from the main terminal after the meter to some sort of separate protection, ie RCD, and then out of this with the 4mm to the garage CU? Is that correct?

Click to expand...

Yes, run tails from main terminal (henley block ) to a single enclosure rcd / rcbo

JONBOY28 said:

2nd query is - I've read on here that I may need an earthing rod, but which type of earthing system does this apply to?

Thanks

Click to expand...

Search exporting PME and garage TT systems- The general consensus is a local earth via rod- a TT system.

before you rip me apart -

So you plan to pay the LABC fee and provide test results ? YES

Please note compliance for Part P, LABC and 17 Edition.... NOTED

you don't know the earthing arrangements in UK systems. That is a TT system......I DO, BUT NEED TO FAMILIARISE MYSELF - THANKS

You also know that this work is notifiable under Part P ? AGAIN, YES

Anyway, i haven't done any calculations yet. Just estimated a 4mm cable. The total run is 30m max, but the catenary run only about 4m. In the garage a couple of fluro strip lights - call it 300w taking into account the x 1.8. A couple of double outlets, 1 for tumble dryer only very rarely - call that 500w? and one for bench grinder now and again, not sure the load. So maybe say 1.5kw? Would that sound about right? Now the voltage drop for 1.5kw given the above info works out that a 4mm is sufficient, and would be for upto about 6kw??

I was going to use rubberised external flex, but if it's not weather proof then Hi-Tuf it will be.

Does this have to be protected on the outside of the flat inside conduit from the eves down the wall where it meets the catenery or can it be clipped direct to the wall - about 4m?

and the garage is on my property so doesn't require wayleaves.