New Garage CU

[Onoff]

The time has come to replace this:

This was the cu that came with the garage. Don't panic it has a lid on!

Tbh that old cu is actually OK for what it is. Incoming, overhead existing SWA top right. The curving SWA at the top is a new cable that goes to the gate with plenty of slack to go into the new cu. White 1mm² out of the top is lights and white 2.5mm² out of the bottom just feeds ONE double socket. All needs a rethink to allow for PV, welder, the EV and a separate breaker for my rotary converter!

Currently fed from the house via a 32A Type B RCBO. The house it TT and the garage has its own rod too. I'll likely replace the 32A MCB in the house with a switch fuse house off Henleys with a Type S RCD.

Rough plan at the mo is a new, all RCBO, Fusebox CU with the following individual circuits:

Lights
Gates
Sockets
Welder
Rotary Converter
EV Charger

(Yes I could get a cheap Chinese inverter(s) but I WANT to complete my rotary converter).

Anything I've forgotten?

PV on the garage roof with a battery? I know absolutely zip about PV, inverters, micro inverters etc, literally no idea whatsoever! Might as well be a foreign language.

First thing is find out what CSA the existing cable from the house is. Thought I knew.....think I wrote it down somewhere.....

Actually joint first thing is to make some space in the garage. There's a stacked shelf in the way of where the new CU is going!

 

[Robotstar5]

If you're lucky some manufacturers put the core size on the sheath, but it's sometimes difficult to read.

 

[Onoff]

If you're lucky some manufacturers put the core size on the sheath, but it's sometimes difficult to read.

I've looked and looked.

It's 4 core 3P cable is all I remember. The spare is taped / heat shrunk over so I can cut a bit off and put a Vernier on it. When I'm sober though.

 

[brightspark]

i sometimes count the cores up and measure one with a dial caliper and measure compare of a known size piece .most times i can tell what size it is just by looking

 

[Onoff]

i sometimes count the cores up and measure one with a dial caliper and measure compare of a known size piece .most times i can tell what size it is just by looking

Exactly what I do with cable. I can generally tell what size a nut or bolt is by looking but not cable.

 

[brightspark]

presumably its xlpe armoured not the old pvc that takes less current rating

 

[Onoff]

presumably its xlpe armoured not the old pvc that takes less current rating

?

It's the red, yellow, blue black far right. Pics from when the new house cu went in. Red line, black neutral, yellow sleeved with grn/yellow for earth and blue spare.

https://flic.kr/p/2pWc3Yz

https://flic.kr/p/2pXwYYC

It's being renewed and in the words of Paul Weller, going underground.

 

[aesmith]

PV on the garage roof with a battery? I know absolutely zip about PV, inverters, micro inverters etc, literally no idea whatsoever! Might as well be a foreign language.

Current requirements are the solar inverter needs to be on a dedicated circuit, the breaker must disconnect both L and N, and if it's an RCD or RCBO it needs to be "bidirectional".

 

[Robotstar5]

XLPE has a higher working temperature than PVC so can carry more current. It may be PVC as it has the "old colours".

 

[RWD3M]

The time has come to replace this:

View attachment 503263

This was the cu that came with the garage. Don't panic it has a lid on!

Tbh that old cu is actually OK for what it is. Incoming, overhead existing SWA top right. The curving SWA at the top is a new cable that goes to the gate with plenty of slack to go into the new cu. White 1mm² out of the top is lights and white 2.5mm² out of the bottom just feeds ONE double socket. All needs a rethink to allow for PV, welder, the EV and a separate breaker for my rotary converter!

Currently fed from the house via a 32A Type B RCBO. The house it TT and the garage has its own rod too. I'll likely replace the 32A MCB in the house with a switch fuse house off Henleys with a Type S RCD.

Rough plan at the mo is a new, all RCBO, Fusebox CU with the following individual circuits:

Lights
Gates
Sockets
Welder
Rotary Converter
EV Charger

(Yes I could get a cheap Chinese inverter(s) but I WANT to complete my rotary converter).

Anything I've forgotten?

PV on the garage roof with a battery? I know absolutely zip about PV, inverters, micro inverters etc, literally no idea whatsoever! Might as well be a foreign language.

First thing is find out what CSA the existing cable from the house is. Thought I knew.....think I wrote it down somewhere.....

Actually joint first thing is to make some space in the garage. There's a stacked shelf in the way of where the new CU is going!

Might I humbly suggest, that time actually came some time ago!

 

[Onoff]

Current requirements are the solar inverter needs to be on a dedicated circuit, the breaker must disconnect both L and N, and if it's an RCD or RCBO it needs to be "bidirectional".

I literally have no idea. Think the bidirectional thing is for the EV charger too?

Have you got a generic diagram of how PV panels connect to the cu?

Cheers.

 

[aesmith]

Have you got a generic diagram of how PV panels connect to the cu?

I don't have a schematic to hand, I could look ours out and blank off the personal stuff but I'm away just now. Our install is similar, panels on the Dutch barn roof, inverter connected to garage DB not to the house CU.

Without a schematic our connection is ..
Suitable RCBO in garage DB -> lockable AC isolator -> solar inverter

Panels and battery both connect as DC to the inverter, so the house electrics only "see" the inverter on its AC side.

Aside from the electrical concerns we also needed a data cable to the house, so the inverter can measure import/export and balance the battery.

 

[addjunkie]

For your car charger you will need a data pair back to the meter tails. Id suggest running that from your meter tails with Henley blocks, with SWA with integrated data pair

 

[Onoff]

For your car charger you will need a data pair back to the meter tails. Id suggest running that from your meter tails with Henley blocks, with SWA with integrated data pair

You mean the data pair has to go all the way back to the house where the meter is?

 

[addjunkie]

You mean the data pair has to go all the way back to the house where the meter is?

Yes, the charger regulates the charge if its going to over load your supply, taking a reading through a CT clamp

 

[brightspark]

u can run a seperate cat 5 back to the ct clamp on the mains tails if using standard 3 core swa

 

[addjunkie]

u can run a seperate cat 5 back to the ct clamp on the mains tails if using standard 3 core swa

I do believe you can get wireless wifi CT clamps, for your charger or solar set up if you dont want to dig in an extra data cable from an out building

 

[Onoff]

Yes, the charger regulates the charge if its going to over load your supply, taking a reading through a CT clamp

View attachment 503285

Ideally I only want to run one SWA from the house to the new garage cu. Thinking I can put the 40A, A Type, DP RCBO in the garage cu?

 

[Onoff]

I do believe you can get wireless wifi CT clamps, for your charger or solar set up if you dont want to dig in an extra data cable from an out building

I'll be running the new SWA in duct from the house to garage. No problem to slip in a 20mm conduit for the data.

 

[addjunkie]

I'll be running the new SWA in duct from the house to garage. No problem to slip in a 20mm conduit for the data.

You can get SWA with cat 5e in it too..search screw fix for EV charger cable…there are cheaper suppliers