Extending ring main for garage conversion?

[CaptainJack88]

I meant - as the person has done it, there was absolutely no point in installing a ring circuit in the garage.
It is not allowed to have more than one socket on a 2.5mm² spur cable without a Fused Connection Unit to limit the current.

When you have changed the spur cable to 4mm² cable it will be compliant and satisfactory.


Actually, I don't suppose the spur cable is 4mm² already is it?

Ah gotcha.
I'm going to check, but I highly doubt it as what I assume we're the original sockets were in there. They wires were relatively easy to fit into the new socket, can't imagine 4mm would be particularly easy

 

[EFLImpudence]

2.5mm² cable has one solid core in each of the 3 wires.
4mm² has 7 strands in each of the L and N, one solid core in earth wire.

 

[CaptainJack88]

2.5mm² cable has one solid core in each of the 3 wires.
4mm² has 7 strands in each of the L and N, one solid core in earth wire.

Ah ok in that case it's not 4mm. All 3 were single solid cores

 

[donrkebab]

Job done, all cable 2.5mm

 

[CaptainJack88]

Looks like when they did the kitchen, the original socket backed out to the spur. Since then, they've moved the socket to the side of where the spur goes through the wall so won't be able to pull the old cable out or use the existing hole.

Guess i'll just have to drill straight through the back of the socket

 

[donrkebab]

Look at the drawing above - post No 19

 

[CaptainJack88]

Look at the drawing above - post No 19

I saw that. The issue I have with that is I have no idea which of the wires are the ring main and which aren't.

 

[donrkebab]

Separate the wires in your the kitchen s/o, and test for continuity, the pair with continuity are the kitchen ring circuit, and the one without continuity is the feed to the garage.

 

[CaptainJack88]

Separate the wires in your the kitchen s/o, and test for continuity, the pair with continuity are the kitchen ring circuit, and the one without continuity is the feed to the garage.

Ah that'd make sense. Best dig out my multimeter!

 

[CaptainJack88]

So, had an electrician out to take a look. What are people's thoughts on this.

Current CU is setup for 2 socket circuits. Left and Right.

On the right side of the house is the kitchen, with kettle, fridge, microwave as the main appliances, plus the usual other stuff you have in sockets. Lights, computers etc.

The ring main extension would be off the same circuit which would then add a 13amp aircon unit, freezer, plus computers etc to the mix, pushing it over the 32A limit of a ring main.

Some rough calculations with everything running at maximum load (im not electrician so I might be wrong)

Microwave. 1.45kw load rating = 6amp
Fridge. 90w "connection value" = 1amp
Dishwasher. 1.8kw = 7amp
Aircon. 1.1kw = 5amp
Washer. 1kw = 4amp
Dryer. 2.4kw = 10amp
Kettle. 1.1kw = 5amp
Also add coffee machine, toaster, server, hairdryers etc etc

Theres also the boiler, but I can't remember if that's on its own CU connection

Thats 38amp if everything is running at once. Remove the aircon and its still pushing 33amp

What I don't understand here is, remove the aircon and you're pushing the limits of a normal kitchen anyway. Forget about the rest of the sockets on the circuit..

 

[donrkebab]

Microwave. 1.45kw load rating = 6amp
Fridge. 90w "connection value" = 1amp
Dishwasher. 1.8kw = 7amp
Aircon. 1.1kw = 5amp
Washer. 1kw = 4amp
Dryer. 2.4kw = 10amp
Kettle. 1.1kw = 5amp
Also add coffee machine, toaster, server, hairdryers etc etc

Theres also the boiler, but I can't remember if that's on its own CU connection

Thats 38amp if everything is running at once. Remove the aircon and its still pushing 33amp

What I don't understand here is, remove the aircon and you're pushing the limits of a normal kitchen anyway. Forget about the rest of the sockets on the circuit..

As long as this used as normal domestic kitchen there shouldn't be a problem, but re-check your stated loads ie m/wave, a/c kettle they seem odd, and is the boiler electric?

All electrical systems have diversity, this is an allowance due to the fact that all those appliances will not be on or drawing full load at the same time.

 

[CaptainJack88]

As long as this used as normal domestic kitchen there shouldn't be a problem, but re-check your stated loads ie m/wave, a/c kettle they seem odd, and is the boiler electric?

All electrical systems have diversity, this is an allowance due to the fact that all those appliances will not be on or drawing full load at the same time.

To be honest, I just grabbed the max load values for the m/wave and googled the kettle as a general rule of thumb. The AC is 10a for max heating/cooling.

The boiler is a gas boiler, so electrical usage would be minimal I assume. Pretty sure its just a "trickle" for the piezo and computer?

In essence though, ditch this electrician as he's talking rubbish?

 

[donrkebab]

In essence though, ditch this electrician as he's talking rubbish?

If he is saying the circuit will be running at 38 Amps, he is wrong. That maybe due to inexperience, it doesn't mean he is incapable of doing this very simple job.

 

[CaptainJack88]

If he is saying the circuit will be running at 38 Amps, he is wrong. That maybe due to inexperience, it doesn't mean he is incapable of doing this very simple job.

I have no doubts he's not incapable I just don't particular want to be paying for a new consumer unit, outside trunking for a new circuit and full house testing if its totally unnecessary It's a £00 vs £000 job

 

[donrkebab]

I have no doubts he's not incapable I just don't particular want to be paying for a new consumer unit, outside trunking for a new circuit and full house testing if its totally unnecessary It's a £00 vs £000 job

No if that's the case, get rid of him.