100amp Switch Fuse required or not required?

[Joshua]

a rat, me thinks has well .some body has been on this forum from Hornchurch?

I'm from Hornchurch

 

[telectrix]

I'm from Hornchurch

my sympathies.

 

[SparkyChick]

Apologies, it's just i was working on council properties previously with another company and they always installed
View attachment 37425
Wylex 100A DP Supply Isolator

but now with another company also working on kitchen rewires and CU upgrades but we are not installing the above. And when mentioned they said due to them not being spec'd by the client so was just wondering whether these are a requirement so the installation has a means of isolation other than removing the main fuse...

So to clarify, if the tails from meter to CU are going to be longer than 3m, the DNOs suggest the installation of a suitable switch fuse to protect the cable run from the meter to the CU as they will not guarantee disconnection times of the main fuse and it's not there to protect your equipment and cabling, it's there to protect the DNO infrastructure.

The installation of an isolator for runs less than 3m is useful as it allows upgrades to be carried out beyond it in the future. Without it, you're in the realms of requiring the seal fairy to come along and hack off the service head or meter seals to isolate the installation for say a CU change. With it, you can safely isolate and lock off the whole installation. But it is optional.

It's also worth noting that some electricity meters also have an isolator on the outgoing terminals which can serve the same purpose. Personally if I'm having the power turned off, I always try and fit one to avoid the hassle of DNO/supplier interaction in the future.

Hope that clarifies things

 

[Input]

Thanks SparkyChick ;-)