Moving MCB from one half of CU to the other

[ninebob]

Hey guys,

Firstly, I should once again say first of all that I am fully aware of Part P but as long as I can get sensible advice here which enables me to do the proposed job safely and in line with regs, the legality of actually being allowed to do it myself or not does not bother me a jot.

Right, that's out of the way, here's the issue:

I have a "dual CU", the top half of which is powered 24hrs and currently has a transformer for the doorbell, and MCBs for shower, lights, socket ring (kitchen), socket ring (rest of flat), cooker radial. The bottom half only becomes live during economy 7 hours, controlled by a teleswitch in the meter cabinet, and has the immersion and 5 radials for storage heaters.

I want to move the immersion MCB. It's ridiculous where it is because 90% of the time we economise and don't use it (we boil the kettle to wash up and use the shower for washing). However, on the odd occaision one of us decides we'd prefer a bath to a shower, you have to plan it the day before. Also, if we do that and one of us runs a full bath first thing in the morning, that's all the hot water gone with no way of overriding it with a boost until the following night!

So, what I'd like is step-by-step instructions to move the MCB to the top half of the CU. As you will see from the photo, I will need to remove the doorbell transformer to make space for it (no great loss as the doorbell doesn't work anyway).

Over to you!

 

[plugwash]

first things first safety precautions when opening a CU.
1: turn off the main switch
2: if its one you have never opened before take great care when removing the cover and as soon as its off check to make sure the incoming tail connections don't have any touchable metal exposed.

swapping the mcbs itself should be the easy bit. they generally have some kind of slip holding them to a rail and a screw onto the bussbar. don't leave empty holes (ie put the mcb that used to be used for the doorbell in the bottom even if you don't actually plan to use it for anything)

you will have to cap off the cable from the doorbell transformer (a peice of chock-block would be ok for this) also depending on how the wiring is run you may have to extend the cable from the immersion heater using chock block or crimps

any other questions?

 

[Agile]

I would wonder if there is really much economy?

Heating the kettle and the shower on peak at about 9p per unit has to be compared with heating the cylinder at about 2.2 p per unit, about a quarter of the cost.

It may well be that improving the insulation on the cylinder and maximising use of off peak would creat more savings.

I used to work with two people who had little timeclocks to put the washing machine and dishwasher on at midnight!

Tony Glazier