Circuit Breaker Query

[Doug99]

Hi Guys 'n Galls
Whilst working on some electrical kit in my shed, the circuit breaker for the house sockets tripped.
My concern is that my shed has its own distribution box and associated breakers: B6 for lights and B32 for sockets
In the photo, my shed breaker B32 and main breaker both tripped, but also my house main consumer unit breaker marked 'sockets'.
Why is this? I would have expected only my shed breaker to trip.
Any thoughts please?
Cheers
Doug

 

[ericmark]

I see 16 amp MCB marked garage, and a 32 + 6 amp MCB in the garage, this should not be the case.

With caravans (often a 16 amp supply) I have seen the 6 amp after the 16 amp, so the 16 amp takes the whole load, and also 10 amp and 6 amp but to put a 32 amp MCB fed by a 16 amp is daft.

I will guess the 32 amp and 6 amp came as standard with the consumer unit, and who ever wired it just used what they had, and never expected the load to exceed 16 amp.

 

[Murdochcat]

I hate to say this but your main CU needs updating

 

[JohnW2]

I see 16 amp MCB marked garage, and a 32 + 6 amp MCB in the garage, this should not be the case.

Certainly not how it 'needs to be' but not in any way 'unsafe' .... and it's probably quite a common situation since, as you go on to say, it's pretty obvious how that that situation has arisen .....

I will guess the 32 amp and 6 amp came as standard with the consumer unit, and who ever wired it just used what they had, and never expected the load to exceed 16 amp.

 

[JohnW2]

I hate to say this but your main CU needs updating

It probably could theoretically benefit by being 'updated', but I've seen far worse in service!

 

[Doug99]

I see 16 amp MCB marked garage, and a 32 + 6 amp MCB in the garage, this should not be the case.

With caravans (often a 16 amp supply) I have seen the 6 amp after the 16 amp, so the 16 amp takes the whole load, and also 10 amp and 6 amp but to put a 32 amp MCB fed by a 16 amp is daft.

I will guess the 32 amp and 6 amp came as standard with the consumer unit, and who ever wired it just used what they had, and never expected the load to exceed 16 amp.

The 16 Amp MCB marked garage only feeds the garage sockets. The 32 + 6 amp MCB is situated in my shed.
My query is to why the house CU 'sockets' MCB tripped rather than just my shed MCB.

 

[Doug99]

I hate to say this but your main CU needs updating

As I understand things, if the CU met regulations at the time of installation, no action is required to update?
What advantage is there to update?

 

[JohnW2]

As I understand things, if the CU met regulations at the time of installation, no action is required to update?

Quite so. Hence my recent comment.

What advantage is there to update?

Probably not a lot. Your present one lacks RCD protection of lighting circuits, which some people might regard as 'advantageous', and Murdo would probably like all the MCBs to be replaced by RCBOs and an SPD to be added (but all of that representing debatable'advantages').
Is the case metal?

 

[JohnW2]

The 16 Amp MCB marked garage only feeds the garage sockets. The 32 + 6 amp MCB is situated in my shed.
My query is to why the house CU 'sockets' MCB tripped rather than just my shed MCB.

Does that men that the shed CU is fed from the house 'sockets' MCB?

When one has two MCBs in series (or an MCB and a fuse in series) it's largely pot luck as to whether one, the other or both will trip/blow in the even of an over-current fault.