House Electrics

Electrical Supply

The electrical supply to the house has had at least three incarnations. First was a two phase supply to the side of the house above the meter box. The entry point, conduit and some of the fabric-covered, rubber insulated wiring were all in place when we took over the house. Second was a two phase supply to a point above bedroom three in plastic covered cable. Again, the entry point and cable were in place when we took over the house. Indeed, the supply cable went through the roof all the way to the switchboard, where it was left dangling. Third is the existing: a three phase supply to a point further above bedroom three. This is done in a single phase neutral/active white sheathed plastic cable pair and two black sheathed plastic single cables. They run as a bundle through the roof to the switchboard.

Electrical Wiring

A tag found in the roof above the laundry shows that the electrical wiring of the house was installed towards the end of 1933. The tag identifies the wiring was from The Enfield Cable Works, manufactured in August 1933. Each wire was tinned copper insulated with "vulcanised India rubber", and wrapped in a fibrous reinforced sheathing of a bituminous material woven fabric. The Enfield Cable Works was granted several patents around that time for their improvements to the insulation of their cables. The wires were carried in black steel conduit, jointed, cornered and T'd as required. It must have been a major task to do the installation, as many conduits had three or even five wires in them and threading them through the joints and Tees would have been hard work.

Although of excellent quality, the Enfield cables and conduit system did not last well. The rubber insulation deteriorated, and the conduits were bent and joints broken in areas where careless maintenance personnel were able to step on them. The main area of damage was in the roof above the switchboard where there is a high concentration of conduits. This is also the area where various additions, including cables for sound-system speakers, and maintenance of the ground-floor air conditioner, took place.

By the look of the more modern cables present, the house was rewired some time in the 1960s, and again in the 1980s. Unfortunately these rewirings were not complete and some of the original 1930s wiring continues in place. Evidently there have been several incidents requiring more and more of the original wiring to be replaced. Indeed, repeated tripping of a Circuit Breaker in wet weather finally culminated in a spectacular explosion and loss of lights in the Dining Room and Office after heavy rain. Investigation showed that rain had entered the roof, and probably dripped onto a broken conduit joint, causing the active wire to short to the conduit and blow apart with a loud bang. Our electrician was greatly challenged in finding this break.

Some of the rewiring and additional wiring of the house was done very poorly. The worst example we found was that all the power points in the Family Room and Bar area were wired directly to one phase of the supply to the ground-floor air conditioner. That is, there was no Circuit Breaker nor Earth Leakage Breaker (ELB) to protect the wiring or users in case of a fault! It turns out that two of the four circuits involved, those using plastic covered cables embedded in the concrete wall rendering, have a high leakage current to Earth, so they could not be connected to an ELB. Unfortunately the bright spark (ho ho) who "fixed" this did so by bypassing both the ELB and a Circuit Breaker so these power points and circuits were unprotected. The current solution is to supply the circuits via a Circuit Breaker that is not supplied by an ELB. This is Phase C3 on the Switchboard.

Nov14: A shocking finding (!) was the wiring in the SE corner of the roof of the pool room. While replacing flashing to cover the barge boards there, I discovered that rats had been nesting there and eating through two electrical cables in several spots. I had blocked access by possums to the area a few years earlier but did not realise that it was more serious, even though a circuit breaker sometimes would drop out when I started up the pool-room ventilation fans.

One of the cables attacked by rats in the pool-room roof is live all the time. The nearness of the bare copper wires and the significant corrosion suggests moisture and sparking. The rats must have received quite a belt while chewing. The nearby nesting material suggests a fire waiting to happen!

The Switchboard

This is located in the Study. It has always been there, with ancient steel conduit still supplying some circuits to the ceiling above. Thankfully none of the dreaded rubber covered and rubber encased 1950s wiring that deteriorates so badly and dangerously has been used.

Dec14: An Earth Leakage Breaker has been added to the Board to protect the circuits in the Workshop, the pool pump, and the solar supply. The corresponding circuit breaker has been uprated from 20A to 32A.

Electricity Meter

Dec12: The time-of-use meter, in place since the solar installation, was replaced on the 12th with a so-called smart meter - a Sprint 200. Now we can see our electricity consumption and generation using a Web browser by month, week, day or half hour using the United Energy portal:

Aerial Supply

Sep14: Our electrican noticed that the aerial supply to the house was about to come adrift. If that happened, and it ripped the fuse junction box from the wall, it would be our expensive problem. As it had not, it was the problem of United Energy.

Four cable ties later, it was fixed.

LINKS

• United Energy http://uemg.com.au/

Electrics

This label was found in the roof above the laundry. It is from the original wiring used throughout. The mfg date is Aug 1933, showing the house was not finished before then and that the structure of the house is largely unchanged after 80 years.

The switchboard in the Study, as we found it.

The switchboard wiring as we found it, with current meter clamps on the three phases.

The switchboard in the Study, as at Dec.2014.

The switchboard wiring as at Dec.2014, with current meter clamps on the three phases.

The original house meter. Was fun to see it spin backwards with solar connected.

"Our" so-called smart meter.

View of original Pool Room Sub-board and switch gear for old pool heater.

Aerial supply cable attached firmly to house. Four cable ties did it.