‘Chasing’ our tails: the electrics

Whoever coined the phrase ‘the old ways are the best’ has never tried chasing out back boxes in solid brick using only hand tools…

For an indecisive soul like me, one of the harder aspects of this project has been all the decision-making. It’s incredible how many choices need to be made: everything from picking a contractor to deciding on the quality of the finish.

Some decisions have been simpler than others. The old back boiler and gas fire, for instance, were well beyond their service life and clearly needed replacing with a combi. But faced with dated but serviceable electrics, we needed to make a choice.

The problem

When we took possession, we knew at least some work would be needed on the electrics. The old Wylex fuse board - fitted with fuse wire - was a dead giveaway that they hadn’t been touched in a long time, but there were other tell tale signs. The different socket styles indicated work had been carried out piecemeal, while the buzzing coming from the living room light suggested not all the connections were as tight as they should be. We also couldn’t be sure the wiring had been upgraded to accommodate the extension (built around 1986). So what should we do to put things right?

The old fuseboard - after being ripped out!

How old is my house’s wiring?

If the wiring had been in old rubber - or even lead - sheathing, then a rewire would have been the only option. But it was the old red and black in PVC sheathing, meaning it was fairly modern, pre 2004. This left us with a decision: do we keep the electrics, and if so, how do we ensure they’re up to spec?

The clearest way forward would be to get an EICR - an electrical installation condition report. This checks everything from the resistance (and therefore age) of the wiring down to the presence of grommets on the backboxes, and gives you a list of problems to fix. However, this would be a waste of money if an electrician could take one look at it and see we needed a rewire, so we decided to get some opinions first.

Opinions…varied. One said it would be fine for at least another ten years (based on a wiring lifespan of 40-50 years); another suggested the insulation resistance could fail at any time, while a third said the wiring was in great condition and of better quality (higher copper content) than brand new wiring. 

One useful tip we learned was that the earth wire is a good indicator of the age of the red and black wiring: a green and yellow earth means it was installed between 1977 and 2004; solid green is pre 1977, and a bare earth means it’s older still. Also, before 1966 there was no requirement to have an earth in the lighting circuit, so this is another way to check the age. It isn’t the end of the world if there isn’t one, but it means you’re limited as to which pendants and switches you can install. If there’s no earth in the sockets, though, it means a rewire.

Another tip the electricians gave us was to look at the socket styles. If they’re different, it might indicate additions and upgrades have been made piecemeal, which would mean there could still be areas of older wiring. Surface mounted wiring is a bad sign, too, while the existence of a brand new consumer unit doesn’t necessarily mean all is well: they could have replaced the CU but not the wiring (a potentially risky strategy, as minor issues on the old wiring might continually trip the sensitive RCDs on modern units).

One of the old painted-over sockets. There were several different styles in the house

My trusty socket tester, kindly bought for me by my sister-in-law and her wife. I'll definitely be taking it along to future house viewings for a quick insight into the electrics!

In the end, given the price difference, we decided on a full rewire. This would give us a fresh start and would mean we could be certain about the quality of the electrics.

A face full of plaster dust

To save money, we decided to do the chasing out ourselves. This is the messy bit, involving cutting into the walls to accommodate the wiring and back boxes. In some rooms we were changing the location of the switches: for instance, the landing light was in the main bedroom (we later discovered this was because the landing wall outside the bedroom was hardboard and impossible to chase out), while we wanted to move the hallway light from the living room to a two way switch at the bottom of the stairs. But we also decided to lower all the switches and raise the sockets to comply with current building regs. There was no requirement to do this as it wasn’t a newbuild, but we felt it made sense to meet modern standards as well as providing uniformity throughout the house.

The rough location of the new entrance hall switch, marked by the electricians, compared to the higher original switch

Current regs state all the electrics need to be between 450mm and 1200mm from the finished floor covering (which requires a bit of guesswork when you’ve ripped up the carpets!) - in other words, the top of the switches can be no higher than 1200mm, and the bottom of the sockets can be no lower than 450mm. Switches should be about 100mm from door edges.

One of the new socket locations. At the top, you can see the white plastic conduit to the old socket, which was in the same location but not the right height for modern regs

Another socket next to the old red and black wiring in a conduit

I marked the relevant measurements with a tape measure, then took spare back boxes for sockets and switches and, using the marked measurements as a starting point, drew around them on the wall. Plasterboard backboxes are slightly different to those for solid walls, made of plastic with clips either side to stop them popping out.

The plastic back boxes for plasterboard with the yellow clips to hold it in place, compared to the metal back boxes below for solid walls, held in by a screw

I then measured a 40-50mm wide channel for the wiring. I wasn’t sure what width conduit the electricians would be using; it turned out they didn’t use it. The wiring needs to go to the nearest void; upstairs, this meant chasing switches upwards (to the attic) and sockets downwards, but because there was a solid concrete floor downstairs it meant all ground floor electrics had to be chased upwards. 

Cutting into the plaster alone would be deep enough for the wiring chases, but depth of the back boxes meant chopping into the brick behind. 

Before cutting, I scored the outlines with a Stanley knife, which massively helped the plaster to break off in the right places without taking any excess. I then grabbed my trusty club hammer and scutch chisel (the comb puts less pressure on the brickwork than a standard chisel), and started.

On of the old back boxes, next to a new chase

Cat’s dad kindly offered to help, and together we chased out about 26 back boxes in one day, along with many wiring chases. The plasterboard boxes were the easiest; they just needed the box cutting out with a knife. Unlike the brick, it didn’t even need the wiring chases cutting (unless it was insulated plasterboard), as the electricians would just thread the wiring through the cavity behind, cutting holes in studs or the wall as necessary.

One long chase in the hallway, with a socket directly below the two way switch at the bottom of the stairs

It was a dusty, noisy day - but a lot of fun too! It’s physically very tough, and next time I will probably look at getting an SDS drill. They have wonderful scoop-shaped chisels and back box attachments that make light work of chasing out. But I’m also very proud of what we achieved just with hand tools. Proper old skool!

This is why we scored the plaster before chiselling: without it, large chunks of plaster might come off in one go

Rewiring day

When the electricians came, they came en masse! There were about eight; they arrived at 8am and had fully rewired the house by 2pm, including a lunch break. Impressive. They’ve done the first fix, which means installing the CU, screwing in the back boxes and installing the wiring (as you can see in the pictures above - I'm afraid I didn't get any pictures of the chases before they came). They’ve left me with a working socket upstairs and downstairs so that I’ve got power at the house. 

A chase in the insulated plasterboard on the living room's outside wall

Coming back down to earth

One other issue was that our cottage is on a TT system. Like all of the electrical work, I don’t fully understand it, but I think it is to do with having an overhead power line to the house instead of underground, as is usual. It means we needed to have an earth rod at the house rather than having the earth supplied; and while we did have an earth rod, there was nothing connected to it. We’d need to have the earth rod tested and, if it was unsuitable, have a new one sunk. However, one of the electricians contacted Northern Powergrid to ask if there was an earth available from their connection. It turned out there was, and they sorted the whole thing by just installing a new main fuse inside the house. Problem solved in a ten minute visit!

Consumer units

The new CU is a split board: this puts the MCBs (miniature circuit breakers) for the downstairs lights and upstairs sockets behind one RCD, and the upstairs lights and downstairs sockets behind another. This means that if a circuit trips an RCD, you only lose half your circuits and will always have some light and some sockets. The old Wylex unit only had one RCD (a later addition, too!) in front of the whole board, meaning that an earth fault on one circuit would knock out power to the entire house.

The old RCD after meeting its fate at the hands of the rewire

There are also RCBOs, where each circuit’s MCB has its own built in RCD. This makes them independent of problems on other circuits, so are good for ‘mission critical’ devices. However, they are more expensive. 

First and second fix

When I’m ready they’ll return for the second fix: installing faceplates on the sockets and switches, connecting the cooker, putting the boiler on a fused spur rather than a socket, and carrying out all the necessary tests to sign off the work. They’ll then issue us with an EIC - an electrical installation certificate. Although an EIC and an EICR are similar, an EIC is issued with new work, and certifies it’s been carried out by a qualified person, whereas an EICR is a report giving a snapshot of the whole installation’s safety. An EIC doesn’t sign off the whole installation, although presumably some installation-wide checks will be carried out.

Is that the end of the wiring? Almost…we were still left with all the holes in the walls that we’d chased out. I’ll leave that until I write about our fun with plastering…