Old electrical installations

There are millions of old electrical installations still in daily use, right across the country. While many of these should be safe and functional, they may not offer all of the facilities and protection mechanisms that a modern install will offer.

This article attempts to collect together notes on the likely pitfalls of older installations, and give tips for how to live with and improve them.

How old?

How do you tell the age of an installation? The Dating Old Electrics page should give you some clues.

General notes on old circuits

Common problems include:

• Lack of RCD protection, greatly elevating the risk of injury from electric shocks.
• Substandard or missing Euipotential Bonding
• Undersized protective conductors in circuits that can result in slow clearing of faults (or even failure to clear in some cases). (on very old installations, proper earthing may not be complete or present at all)
• Badly perished rubber insulation creating a high risk of insulation failure.
• Light switches that can sit in mid position, and if luck deserts you, sit in an almost on position and arc. This either burns the switch out or causes a fire.
• Dirt buildup at connection points. This can cause [[Electrical_Circuit_Faults|circuit faults], insulation breakdown, and fire & shock risk.
• Poor connections. Connections can deteriorate due to decades of thermal cycling, wire corrosion, or less than ideal design & construction of historic fittings.
• Flammable wiring enclosures, such as wooden pattresses behind light switches and sockets.
• Light switch covers that undo easily by hand, a danger primarily to children.

What old installations may be missing

The most common omission is RCD protection, which reduces risk of shock, and to a limited degree fire.

etc.

See Also

• Wiki Contents
• Wiki Subject Categories