Tripping MCB

[Rob2011]

I have this RCCB unit (View media item 38062 ) connected to our shed and have connected a socket from it and lights, where my wife grooms dogs.

All is ok until she uses the dog dryer ? (Power: 2900 watts.) Then as soon as she turn the dryer up the MCB trips.

Not sure what the fault is could it be an earthing fault ? Or could it be that the dryer is to much of a load on the MCB ??

Or could it be something completely different ? Please help ?

 

[holmslaw]

..

 

[westie101]

So the photo shows a RCCD, a 16A MCB and a 6A MCB.
Exactly which one is tripping?

 

[Rob2011]

So the photo shows a RCCD, a 16A MCB and a 6A MCB.
Exactly which one is tripping?

The one on the right (number 2) the other one is not connected yet..

 

[westie101]

Must read posts more carefully before replying

 

[Paul_C]

The one on the right (number 2) the other one is not connected yet..

You mean you have a 13A socket you're using for the dryer running on the 6-amp MCB?

6A x 240V = 1440 watts. That's why it's tripping with a 2900-watt load.

 

[PrenticeBoyofDerry]

It sounds like the circuit is overloaded.
A 6A MCB will only be able to carry a load of 1380 Watts.
So as soon as your your 2900 watt dryer is operated it will trip.
The dryer needs 13Amp.

 

[PrenticeBoyofDerry]

I suggest you use 6A mcb for lighting circuit and change the 16A mcb to at least a 20A, if the dryer is going to take 13A up.

 

[Rob2011]

So how many lights are connected and of what size, what else is connected?


You should also realise that the lights should probably be connected to the 6A MCB if you have used cable other than 2.5mm2 for them

The lights are on a smaller cable but,,, they are connected via a Fused Switched Connection Unit, would this be ok ?

The lights are: 2 Fluorescent strip lights and theres not much else being used when the dryers being used just lights really posible radio..

 

[PrenticeBoyofDerry]

Hello can you hear me
2900watts way to high for 6A MCB regardless of anything else you have on your circuit.
Get you circuits designed right.
6A MCB for lights
16A MCB plus for dryer.

 

[Rob2011]

Hello can you hear me
2900watts way to high for 6A MCB regardless of anything else you have on your circuit.
Get you circuits designed right.
6A MCB for lights
16A MCB plus for dryer.

Yep can hear you was replying to westie101, but thanks anyway for your advise

 

[PrenticeBoyofDerry]

Yep can hear you was replying to westie101, but thanks anyway for your advise

Rob2011,
don't thank me anyway!
Follow the instruction I have given or the problem will continue.
What size breaker do you have protecting the cable that is supplying the shed consumer unit.
This may allow you to increase the size of the 16A MCb to a more suitable size for the socket circuit, as I have said the dryer will need nearly 13Amps for it's full load.
This will only leave you 3 Amps of the 16 Amps of the existing breaker for any additional electrical equipment on that circuit, Once you have removed the dryer from the 6A circuit.

 

[Rob2011]

Yep can hear you was replying to westie101, but thanks anyway for your advise

Rob2011,
don't thank me anyway!
Follow the instruction I have given or the problem will continue.
What size breaker do you have protecting the cable that is supplying the shed consumer unit.
This may allow you to increase the size of the 16A MCb to a more suitable size for the socket circuit, as I have said the dryer will need nearly 13Amps for it's full load.
This will only leave you 3 Amps of the 16 Amps of the existing breaker for any additional electrical equipment on that circuit, Once you have removed the dryer from the 6A circuit.

No... I deff will follow your instructions...
Will check what size break I have supply the shed.

The reason I havent used the other mcb, was because we needed to supply power to a heated bath and pump so was going to use the other mcb for that.

Could I change both to 20A, would that be too much ?

New to this forum and I do appreciate the help. Thanks

 

[PrenticeBoyofDerry]

There are lots of things that can be done with the way the circuits are designed.
But first off we need to know what size breaker is supplying the shed.
The isolator says a max of 40Amps.
So if you have 40Amps protecting the cable that is supplying the shed we can do divisions of that.
You could use the 16A breaker on your lighting circuit with the use of the down fused FCU you have or increase the cable size of the lights to 1.5mm, if the lights are not rated at more than 782 watts, it would then be possible to have your dryer on that circuit.
Then you could have a 20A breaker for another circuit to service other equipment.
Please remember that most of this work is classified as notifiable work in England and Wales.
http://www.diynot.com/wiki/electrics:part_p