Fuse size for sy plan am2

[Jakegood]

Hi,

Can anyone who has passed there AM2 please tell me what size fuse they used for the sy heating plan. It is fed from a B16. So, would it just be a 13a? I have seen them just on a 3a before.

Cheers

 

[Flash]

It used to be on a B6 breaker so I would use a 3 amp, are you sure its on B16 as if so this has changed.

 

[Strima]

It will state on the installation plans you get what size fuse to use.

 

[Jakegood]

Defo 16. I have always seen them on 6? Obviously wouldn’t put a 3amp fuse on 16amp breaker? The spec tells you the cable size and breaker size, not the fuse?
Just wondered if anyone had taken the am2 recently to clear it up?

 

[Jakegood]

This is the spec

 

[SparkyChick]

Obviously wouldn’t put a 3amp fuse on 16amp breaker?

Just out of interest.... why not?

Edit:-

The MCB is there to protect the cable... the fuse is there to protect the equipment.

 

[casperLennon]

I think it’s already in.

 

[Jakegood]

just thought its common to have a 6 amp with 3 amp fuse?
they give you a box full of fuses and breakers etc. you have to chose the correct type. has anyone done the am2 recently?

 

[casperLennon]

Not everything they give you will be used. I’m sure it’s in already

 

[mhar]

On the spec it states heater and hot water, refer to seperate diagram. Wouldn't that be where the answer is?

 

[Jakegood]

no, that just a wiring diagram of the heating system. I want to put a 3 amp fuse in it. just want to be sure. would be my luck to fail on something like that. just though the heating would be on 6amp with a 3 amp fuse.

 

[SparkyChick]

I normally install 2.5mm on a 16A MCB and then fuse down to 3A using a SFCU. This gives some scope in the future for additions. Say a shower pump for example which may well be located nearby.

The fuse required by the heating system would normally be specified in the installation manual for the boiler, but a 3A is a fairly safe bet.

 

[Strima]

no, that just a wiring diagram of the heating system. I want to put a 3 amp fuse in it. just want to be sure. would be my luck to fail on something like that. just though the heating would be on 6amp with a 3 amp fuse.

Don't think about what size fuse to put in, follow the installation document and you can't go wrong.

 

[davesparks]

just thought its common to have a 6 amp with 3 amp fuse?
they give you a box full of fuses and breakers etc. you have to chose the correct type. has anyone done the am2 recently?

Nope, small appliance supplies are normally a 16A radial because this is the smallest standard power circuit.
Whether a 13A or 3A fuse is used in the switches fused spur will depend on the appliance, a domestic gas boiler is normally a 3A fuse.

 

[Jakegood]

So, just go for the 3 amp fuse then. Has anyone actually done the latest am2?