Dodgy house wiring - need to replace?

[TomH]

Hi there all,

We've recently bought a 1930's house with a couple of extensions (probably 1960's then redone in the late 1990's). I painted this during winter and had a few (3) heaters running to assist in the paint drying process, and noticed that we were tripping the circuit breaker on one circuit (circuit 6). We mapped out the circuits and found out that nearly every power point is on circuit 6.

It has a separate garage down the back, with one cable running to it (3 core 2.5mm). Lights and power all on the same circuit. 4 double power points on it so the load looks ok. I needed to install an additional fluoro tube and move a power point and so isolated this so I could hook it up. Found out it is also on circuit 6.

I then pulled the cover off the switchboard to do some current measurements on circuit 6, as I know this circuit is overloaded (19 double power points + 4 in the garage + window rattler aircon and a 15amp plug). Circuit 6, 7 & 8 are protected by an RCD. To my suprise when opening up the panel I found there are no wires connecting the RCD to anything. I also found when I turned off 6 it turned some of the lights off in the extension.

So, I knew I had potentially overloaded wiring but now I find out that my house is not protected by an RCD. This is concerning as I have two small children who could stick forks into powerpoints. I also know that I have mixed light and power circuits.

I am assuming the RCD is bypassed as it is generally overloaded and the aircon is installed on this circuit, so it tripped lots and they removed the wires.

I will get some quotes from electricians but was interested as to what I should be aiming for:

1. There are two circuits with only one power point. I could get them to sort out the aircon onto a separate circuit and then split the house and the garage.
2. Assume that it's been done by someone dodgy and rewire the whole house.

Any input as to the best course of action would be appreciated.

I am pretty happy to relocate a power point or hook up a fluoro tube, but rewiring a house and installing RCD's is something best left others. Having said this, when I see that there is an electricians sticker and current phone number on the box I can't help but thinking I could do a better more legal job.

Cheers,

Tom

[Master Splinter]

I would assume number 2, and do the following:

Go around all power points with a tester to verify correct polarity and earth connection.
Pop all points and switches out of the wall and inspect wiring condition and size.
Rework the power circuits to split the heavy loads across more than one circuit, including putting the garage on its own breaker (and maybe a sub board in there to split lights/power over two circuts, as there's nothing more annoying than popping a breaker at night and stumbling in the dark). You can get combined RCDs/Breakers so each circuit is protected individually, so one nasty appliance doesn't take out the whole house.
Aircon on its own circuit.
Lights on their own circuit(s).
I think 15 amp plugs should be on their own circuit, too (I'm just guessing here, haven't looked it up).

And...what rating is the breaker or fuse on circuit 6????

[applied]

Rewire is most likely required the you might be able to save the 1993 part.
I have seen something simmilar in a old house the owners had moved the all the actives to one fuse over many years as the fuse holders burnt out. You might find if you seperate all them and megger them out with some invesigation you can save some of the existing stuff however I suspect you will find metal conduit in your roof if you do don't even get up there that's deadly stuff.
If you recently bought the house I would be contacting the agent because it is illegal to disconnect rcds and the owners may have had a responsibility to disclose non approved building work might be worth seeing if your extention has approval.

[NigeC]

Something was tripping the rcd so instead of solving the problem it was disconnected.

Depending on how old the older part wiring is, with the number of problem circuits and A/Con linked in maybe a rewire would be beneficial.

[TomH]

Thanks for the replies - 3 out of 3 suggesting rewire is fairly consistent!

To answer a couple of q's:

- 20a breaker on circuit 6.
- There are metal conduits running along some of the beams. I assumed they were lighting circuits, but they might be power. I had no idea these are dangerous.
- The extension cabling is run underneath the ceiling battens. There is insulation over some of it. I have tried to replace the insulation so the cables are on top, but with the cables running underneath the battens this is near impossible.
- Circuit 5 is also not in use (labelled light / power).

I have also included a couple of photos of the board showing the imaginery RCD wires and one of the older power points. I have blacked out the electrician service names from the front of the panel.

I've had a few points off to look at the wiring. 50% of the powerpoints in the old house are like the photo shown. Solid wire with very limited flexibility (i.e quite hard to get the power point off the wall).

Cheers,

Tom

[applied]

it doesnt look like a total write off yet i would still be investigating getting the switch board tidyed it would appear the house has had some signifcant upgrade already as only a couple of those have unsheathed earths.

just out of curiosity is this switchboard indoors or outside behind the old wooden doors. and are all the gpo's that close to the carpet? if so rewiring upto spec may be a extraordanarily expensive job.

your definately going to have to bring it up to spec but from what your showing its not in disrepar it is possible the rcd was disconnected as a tempory measure that has just been forgotten or ignored.
i work for a 24hour service department it youst to be practice to disconncet rcd's if the fault could not be rectified at say 3am and then go back next day and investgate the owners may have just not followed up.

i would suggest you stop poking around in there thou unless you know how everything works and call a pro who has the right test equipment.

[NigeC]

I agree with Applied.
A new switchboard, sort out your circuits, get light and power on RCD, not too many bare earths meaning a limited rewire, swap main switch for CB, is there even an earth stake?!?!?!

[GraemeCook]

Good Morning Tom

I had a similar experience some years ago when I bought a house that had been allegedly totally rewired by a dangerously incompetent sparkie. (Much debate on this forum if you want to search; but let's not repeat it here.). I later found lead coated wiring still in use!

If you have pre-1960's (or thereabouts) wiring - whether lead or fabric covered - the conductors will be sheaved with natural rubber insulation. This rubber will now be perished & crumbly and potentially dangerous. It should be replaced with some urgency.

Your more recent wiring should be safe, but I would still get it checked for peace of mind - there are still some cowboys out there. And remember, its illegal to do any fixed wiring work yourself, fines/accidents are a risk and it can invalidate your insurance, as can doing nothing.

I would add a third option to your list:
* Get a sparky to do a thorough inspection, advise what must or should be replaced and to balance the loads as needed. This could be an expensive exercise, depending on extent of work and ease of access. [eg. My internal walls on an 1870's house are plaster on double brick (no cavity) and wiring was imbedded in the plaster and had to be removed, replaced and the plaster restored.]

Sorry to be so mournful.

Cheers

Graeme