Replace 16Amp MCB & 2.5mm T&E with 32Amp MCB & 4

[KevinPeters]

Hi all

One of my MCB's is rated at 16A and has running off it a single spur to a socket in the garage and to a FCU onto the Combi boiler in the kitchen.

When plugged into the socket in the garage, my 1400w chop saw trips the 16A MCB. If I use it on an extension from the 32A downstairs ring it works fine.

1. I am surprised that it trips the MCB as it is only ~6A. I suspect that the draw is momentarily higher when the saw spins up. Anyone have any opinion on this?

2. So, what I would like to do is replace the 16A MCB with a 32A one. I understand that I will have to replace the 2.5mm T&E cable that runs into the garage with 4mm. Is this correct?

3. I would like to add an additional double socket in the garage (just for drill charger, portable light etc). My understanding is that my circuit is a radial one, and because I am using 4mm cable I can just continue the radial from the first socket (i.e. a spur off a spur). Is this correct?

4. Will changing the MCB for a 32A one have any impact on my combi boiler circuit?

Thanks in advance
Kevin

 

[ricicle]

You could swap the mcb for a 16A Type C if it is a Type B but this will require correct testing at the extremity of the circuit to ensure that disconnection times are still met.

 

[EFLImpudence]

1. I am surprised that it trips the MCB as it is only ~6A. I suspect that the draw is momentarily higher when the saw spins up. Anyone have any opinion on this?

Maybe

2. So, what I would like to do is replace the 16A MCB with a 32A one. I understand that I will have to replace the 2.5mm T&E cable that runs into the garage with 4mm. Is this correct?

You could just replace it with a 20A or 25A depending on the cable route.
Or C type mcb depending on the circuit loop impedance.

3. I would like to add an additional double socket in the garage (just for drill charger, portable light etc). My understanding is that my circuit is a radial one, and because I am using 4mm cable I can just continue the radial from the first socket (i.e. a spur off a spur). Is this correct?

Yes, also extendible with 2.5 mm² if you do the above.

4. Will changing the MCB for a 32A one have any impact on my combi boiler circuit?

No.