Garage Consumer unit

[blightfoot66]

Hope someone can advise???

I have had the old fuse type consumer unit in the house replaced with a new one.

In my garage is a second small garage consumer unit that supplies power to three twin sockets and two lights in the garage. It also supplies power to two twin sockets and a light in a workshop atatched to the garage and also to one twin socket and a single light in a utility room on the other side of the garage.

My problem is, when the new consumer unit was installed in the house (by a qualified electrician), the mcb that powers the garage consumer unit continually trips!!!!

I am assuming that there is two much running off the mcb which is rated at 16a. The cable running to the garage consumer unit is 4mm.

My question is can the mcb be increaesd to prevent the tripping or should the consumer unit in the garage be changed for a larger one to distribute the power to the three seperate socket and three seperate lighting circuits?

If its the latter will the 4mm cable running to it be ok or changed for a larger one and will the 16a mcb at the house consumer unit need increasing?

Any advice greatly appreciated

 

[Steve]

When the MCB trips, is anything actually running on that circuit?

I'm thinking its actually an RCBO. Does it have a test button on it?

 

[Taylortwocities]

Did this trip when the qualified electrician installed new consumer's unit?
Or did it start some time afterwards?

Did he test all circuits, did you get a copy of the results? What was the Insulation Resistance measurement for that circuit?

 

[blightfoot66]

When the MCB trips, is anything actually running on that circuit?

I'm thinking its actually an RCBO. Does it have a test button on it?




The cable is definately connected to a 16a mcb in the house consumer unit

If you are talking about the garage consumer unit, its very old and does not have any trips on it. It has the old type push in fuses

 

[blightfoot66]

Did this trip when the qualified electrician installed new consumer's unit?
Or did it start some time afterwards?

Did he test all circuits, did you get a copy of the results? What was the Insulation Resistance measurement for that circuit?

It did not trip straight away but when things were used it tripped.

He tested all house circuits but not the garage ones

 

[Monkeh]

Are you actually pulling 16A in order to trip it?

 

[blightfoot66]

Are you actually pulling 16A in order to trip it?

No. all the sockets and lights are not all being used at the same time, could you advise how much of what I have on the circuit would need to be running to push the 16a limit?

 

[Steve]

16 amps is about 3700 watts.

But to trip it within a second, you'd need to be pulling over 30 amps. It will run at 17 or 18 amps practically forever.

 

[blightfoot66]

16 amps is about 3700 watts.

But to trip it within a second, you'd need to be pulling over 30 amps. It will run at 17 or 18 amps practically forever.

So what does 6 twin sockets and five lights pull???

 

[Monkeh]

16 amps is about 3700 watts.

But to trip it within a second, you'd need to be pulling over 30 amps. It will run at 17 or 18 amps practically forever.

So what does 6 twin sockets and five lights pull???

The sockets don't unless something is connected to them. The lights could pull anything from 7W each to 1500W each, we don't know without knowing what they are..

 

[Steve]

A socket pulls nothing. What are you plugging in to the sockets?

A light pulls whatever its wattage is!

 

[blightfoot66]

16 amps is about 3700 watts.

But to trip it within a second, you'd need to be pulling over 30 amps. It will run at 17 or 18 amps practically forever.

So what does 6 twin sockets and five lights pull???

The sockets don't unless something is connected to them. The lights could pull anything from 7W each to 1500W each, we don't know without knowing what they are..

Two of the lights are 4ft flourecents, the other three are standard battens with 60 watt bulbs.

With regard to the sockets the only things permenantly connected are a compressor (small garage one) and a bench grinder....

 

[Monkeh]

Well that's nothing like 16A. Now, what are you using when it trips? Any specific tools or sockets?

 

[Taylortwocities]

And there should be discrimination.

What fuses are in the garage fusebox? What are the values of each and what do they serve?

They should be less than the 16A in the house. The idea is that the garage fuse will pop rather than the house one.

And, is there an RCD on this circuit, somewhere?

 

[blightfoot66]

And there should be discrimination.

What fuses are in the garage fusebox? What are the values of each and what do they serve?

They should be less than the 16A in the house. The idea is that the garage fuse will pop rather than the house one.

And, is there an RCD on this circuit, somewhere?

The garage consumer unit has two push in fuses one running all six double sockets 16a and one for all five lights 6a

There is an RCD in the new house consumer unit, but on the old garage one there is just the two fuses and the main switch