In article ,
"dennis@home" writes:
On 29/01/2018 13:05, jim wrote:

Does retrofitting mcbs into an older wylex "fuse wire" consumer
unit need notification?

The plug in ones don't have the same breaking capacity as te fuse wire
so you may need to check they are OK.

The original push-button plugin ones are 1kA breaking capacity,
which is the same as the Wylex BS 3036 rewirable fuse carriers.

The newer toggle plugin ones are 3kA breaking capacity.

So this isn't an issue, although if you get a new consumer unit
which takes only MCB's, they will probably be 6kA breaking capacity
(or 10kA for an industrial one).

However, a 100A (or lower) main cutout, if it's an HRC cartidge
fuse, increases the effective breaking capacity of the fuses
(and MCBs) so this isn't generally a significant issue.

But why bother? I haven't had a fuse wire go in 30 years so fitting MCBs
would be a waste of time IMO.

The Wylex BS 3036 rewirable fuses don't provide sufficient
protection for most ring circuits, when you've applied the
derating factor to the cable for using them.

--
Andrew Gabriel
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