Adding an furth 63A load

uksparks · Dec 11, 2014

Hi,

What are your thoughts on adding a further 63A load to this board? It will be using 63A too, not just a few amps of it as its a for a twin car charger.

[ElectriciansForums.net] Adding an furth 63A load

looking at it, theres a max load of the following if everything was maxed out.

L1: 126A
L2: 193A
L3: 211A

I need a 63A single phase supply, so my gut instinct says put it on L1, but to you feel im adding a lot of extra load to the board? I know its not a huge amount but just wondering what your thoughts were?

Obviously taking diversity into account etc, its not over the top, its only an office. The two 63A supplies on L2 and L3 on 35 and 36 are not in use at the moment but will be shortly.

The other part of the issue is, getting armoured cable out of the wall, its got to come from about 2.5 meters up the wall, down then into the ground. I don't really know which way to tackle this as I want it to look really neat and tidy for the customer. The cable is then going into the ground outside.

I can get away with 10mm SWA to feed the charger unit, but not 100% sure the best option really to get it looking nice on the wall, then theres this bit at the bottom at juts out.

I did look at running non armoured cables to an adaptable box on the outside then glanding the SWA to that and straight down, but ideally i don't want to use an RCD / RCBO to feed it as the unit has two RCBO's built into it.

Engineer54 · Dec 11, 2014

If those other 2 63A breakers are also going to be loaded up, then your getting pretty close to maxing this 3 phase 100A DB for real ...lol!!

uksparks · Dec 11, 2014

Well they are only for two offices, both are about 10m x 6m, so not huge, so unless they are growing something, then I doubt it.

Deleted member 72666 · Dec 11, 2014

It's hard to tell without measuring etc but from what I see L1 is the least loaded phase, if the last 2 ccts are only small offices then can't you fuse them down to 32amp then that way it'll go a long way to stop them being abused in the future by numpty sparks who'll see them as 63 amp available load.
Edit:
What are the numbers referring to written in biro on the left hand side, are they the actual circuit numbers?

uksparks · Dec 11, 2014

To be honest I have no idea, thats all written on a piece of plasterboard propped above the distribution board... not very good for a new install is it, i dread to think what it will look like inside.

Yes thats not a bad idea, I could drop them down to certainly 40A breakers which would assist, or like you say 32A, that then frees up a bit, to be honest, i bet they are only pulling less than 10A anyway, ill have to measure it.

What do you think about the outside bit? I don't know what to suggest.

Plonker 3 · Dec 11, 2014

Why would swapping existing MCBs help? The current drawn will still be exactly the same.

Plonker 3 · Dec 11, 2014

If the cable is being buried then SWA externally certainly, to get it to ground level use galv trunking as that wont look out of place attatched to the outside of that type of building.

Guest77 · Dec 11, 2014

Re: Adding an furth 63A load ------------ ??? perdón

davesparks · Dec 11, 2014

Eddy currents anybody?

Fin170 · Dec 11, 2014

Dillb said:
Why would swapping existing MCBs help?

Because the ones on the left side of the board are all clearly drunk

Is the charging point going to have its own earth rod? (more out of interest than anything)

ferg · Dec 11, 2014

davesparks said:
Eddy currents anybody?

Oh ye of little faith.

cdavies33 · Dec 11, 2014

davesparks said:
Eddy currents anybody?

Yeah, seen it. 2 tails through a 25 mm stuffer. Board schedule written on a white board. It's been wired by a chancer for sure

Bait Account · Dec 11, 2014

UK have u applied diversity to that lot? As for the bit outside bung a bit of metal top hat over the swa and it'll look sweet.

Guest55 · Dec 11, 2014

having spare capacity in the DB is only half the story , you need to check the potential of whats upstream.

and i'd use 50mm tray on top hat brackets for the cable run down the side of the building then cleat along that row of bricks above the gravel , with strip grommet and silicon for the wall penetration.