How do Electricians change consumer units with live wires?

[vonsworld]

I have always wondered how electricians work with live wires when changing consumer units? Presumably you don't pull the main fuse that belongs to the network and so have to connect live incoming wires? Do you wear thick rubber boots?

I should point out I am just curious, I have no plans to change a CU myself! Would always hire a professional.

 

[EFLImpudence]

I have always wondered how electricians work with live wires when changing consumer units?

We don't.

Presumably you don't pull the main fuse that belongs to the network and so have to connect live incoming wires?

Why do you say that?

Do you wear thick rubber boots?

No, very clever ones.

I should point out I am just curious, I have no plans to change a CU myself! Would always hire a professional.

Ok.

 

[Rodders53]

Most modern installs have a DP isolating switch in the meter cupboard between meter and consumer unit elsewhere.
If not, many now will demand the customer gets such an isolating switch fitted by the DNO before changing the consumer unit.

Not many now will pull a DNO fuse - but some areas I read allow 'authorised' electricians to do so and then re-seal the fuse at the end of their works (and they'd likely fit a DP isolator switch at the same time I hope)?

The real question is how do those people who are fixing the mains cables underground manage to do it... in the rain...
It was quite fascinating to watch the man up our local pole connecting up a 3-phase cable to a new house. Obviously live as our power stayed on.

 

[blup]

Electricians pull the main fuse to avoid being fried, John Ward had a good video around it on youtube. I fitted an isolator to get round the problem.

Blup

 

[DetlefSchmitz]

As a matter of interest, if I had my meter changed and they agreed to fit an isolator, can anyone point me at the typical model they would fit?

 

[RandomGrinch]

can anyone point me at the typical model they would fit?

Mine was a Wylex, although fitted a few years ago by the DNO:

Wylex 2 Pole Isolator Switch With Enclosure

If you are carrying out electrical installation or maintenance work, turn to this Wylex two pole isolator switch with enclosure. This handy piece of equipment works to power down appliances or circuits to stop electricity running through it, ensuring maximum safety when you're testing or...

www.toolstation.com

 

[jacko555]

When the smart meter, and again when the EV charger was installed, the main fuse was pulled. Neew metal crimps added to the holder after and a new "do not remove" anti tamper sticker stuck on.

I asked the same question.

 

[vonsworld]

Thanks for your replies, which all make perfect sense. I thought the network operator only was allowed to remove the main fuse, hence my question.

 

[EFLImpudence]

Thanks for your replies, which all make perfect sense. I thought the network operator only was allowed to remove the main fuse, hence my question.

'They' like to promote that idea by saying things like it is their property - but it is in your property.

I do believe that in the relevant regulations 'they' are not allowed to "unreasonably" refuse permission to pull the main fuse if necessary - but of course you should know how to do it properly.

 

[AdrianUK]

The real question is how do those people who are fixing the mains cables underground manage to do it... in the rain...
It was quite fascinating to watch the man up our local pole connecting up a 3-phase cable to a new house. Obviously live as our power stayed on.

There are safe working procedures developed to do this.

I don't want to go into too much detail on a public forum but such methods involve techniques such as only exposing one live conductor at once & using insulting tools & gloves.

 

[Rodders53]

As a matter of interest, if I had my meter changed and they agreed to fit an isolator, can anyone point me at the typical model they would fit?

My (faulty) electric meter was recently changed and my supplier fitted a Proteus model (with supplier logo stickers) that has double-screw cable terminals to replace the single screw terminal version fitted when the place was built.
Needs a 3mm hex screwdriver.

100A Double Pole Isolation Unit with Twin Terminals

Meter isolator switch

www.cef.co.uk

 

[flameport]

how electricians work with live wires when changing consumer units?

They don't.
The supply is disconnected first, either via an isolator if there is one, or the main fuse if not.

Not only is live working dangerous, it's also against the law.

 

[Harry Bloomfield]

Mine was a Wylex, although fitted a few years ago by the DNO:

Wylex 2 Pole Isolator Switch With Enclosure

If you are carrying out electrical installation or maintenance work, turn to this Wylex two pole isolator switch with enclosure. This handy piece of equipment works to power down appliances or circuits to stop electricity running through it, ensuring maximum safety when you're testing or...

www.toolstation.com

That is the very same one I fitted..

 

[plugwash]

There are safe working procedures developed to do this.

I don't want to go into too much detail on a public forum but such methods involve techniques such as only exposing one live conductor at once & using insulting tools & gloves.

I've heard of such procedures for jointing cables and changing service cutouts, but not for changing CUs.

 

[Mottie]

Years ago when I had an electricity supply installed to my workshop, they dug up the pavement and stripped the insulation from the main underground cable. They then exposed the main cables within (live and neutral) stripped them back to metal and soldered the cables going to my main fuse/meter. When that was done, they put a plastic casing shell around the new connections and filled it with some kind of resin to seal it. They did all this while it was live. Before they came, they delivered a couple of metal spikes and I had to hammer them about 6 feet into the ground. That was for the earth.