Upgrading RCBOs

[Pipe Dreamer]

The consumer unit in my garage has Hager MT116 breakers for the wall sockets. As I understand it they are type B single pole 16A.
There's a 17mm armoured cable going into the consumer unit which I'm pretty sure is fed from the consumer unit in the house.

I'm planing on using a welder rated at 40A so need to upgrade at least one of the breakers.

1) Would it be correct to swap a 16A breaker for a 40A type C RCBO?
2) Is there really anything more to it than shutting off the master breaker on the MCB, pulling out the 16A breaker and plugging in a new one? (Does this really need an electrician and a callout charge?)

 

[Robotstar5]

The consumer unit in my garage has Hager MT116 breakers for the wall sockets. As I understand it they are type B single pole 16A.
There's a 17mm armoured cable going into the consumer unit which I'm pretty sure is fed from the consumer unit in the house.

I'm planing on using a welder rated at 40A so need to upgrade at least one of the breakers.

1) Would it be correct to swap a 16A breaker for a 40A type C RCBO?
2) Is there really anything more to it than shutting off the master breaker on the MCB, pulling out the 16A breaker and plugging in a new one? (Does this really need an electrician and a callout charge?)

17mm is the OD? not the CSA (cross sectional area) of the cable which is important to know how much current it can supply and you're "pretty sure" it's fed from the CU in the house?.

Changing from a B type to C type MCB also affects how quickly it will disconnect the supply under fault conditions and has to be within certain limits stated in the wiring regs.

Probably best to ask a qualified Sparky?.

 

[barracuda816]

What you want to achive depends on;

How the garage consumer unit is fed. It is usually fed from the main consumer unit in the house, so you will need to see what MCB/RCBO it has in that.

The Size of the Armour cable conductor cores. 17mm SWA if its three core would probably be 2.5mm in which case you cant put in a 40a MCB. It also depends on how the SWA is run and how long it is.

Also how big the cable size and length of run to the socket for the welder (40A is quite alot for a single phase welder, are you sure it requires this much)

Also some other calcs such as Zs values need to be taken into consideration and installation methods. It will likely need to be RCD protected (but if you are looking at RCBOs then you already know this).

Deffinatly requres a chat with an electrician IMHO

 

[Pipe Dreamer]

Note to self. Need a sparkie.
Thanks for confirming I don't know enough to do it myself. At least I now no enough to know if a sparkie is qouting for the right sort of things.

 

[Pipe Dreamer]

Almost forgot. Have double checked the welder size rating. (Jasic 200P AC/DC Mini) Its 30A.
But I still need a sparkie. :-)

 

[normspanners]

I'm planing on using a welder rated at 40A

Its 30A

especially need a sparkie me thinks some serious melting can occur and not at the welding tip