That came about with the "safety switch" craze of about 30 years ago when they became mandatory on all new domestic installations or where alterations and additions had been carried out. It wasn't compulsory to have one switch control the whole house but people preferred it because it was much cheaper.

The standards now mandate an RCD for each light and general power circuit but of course they are a lot less expensive than they once were. They are, sadly, also less reliable than they once were - meaning that some of them fail with the usual surges, spikes and brownouts that regularly pollute the electrical supply these days due to solar and wind installations switching in and out of the grid.

The original "one does all" approach copied the way the old voltage-operated earth leakage circuit breakers were wired in. These did the same job as a residual current device but detected voltage on the earth cable in the meter box rather than a current imbalance across a circuit.

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A valve a day keeps the transistor away...

Probably the same moron that is having Road barriers installed on rural roads to make them more dangerous. We had a flood on the Freeway up here and I don' know how many millions that will cost in drowned cars etc. that could not turn back

The irony of that was, that had the barriers not been there, probably 90%+ could have been saved by just driving them a car length up the embankment of the other lane.

I think they idea of RCD's is to help protect idiots that will insist on messing with the mains. Albeit they have some benefit & the Yanks have them so we can't be left out. They call them GFCI's

Aside from that we have a bureaucracy in this country that traditionally goes out and finds things like an all encompassing empire like the "Department Of Transport" which absorbed & did away with entities like DCA & is why we now have CASA.

This was a classic like solid welding rail & road barriers which most of the world is pulling as they are dangerous,. This "absolutely brilliant" (sic) idea that they found was implemented with the usual gusto, fanfare and world saving spin, had never worked in Canada, USA, England, and pretty much every country that tried it, thereby making it an absolute "priority one" for a must have here.

These did the same job as a residual current device but detected voltage on the earth cable in the meter box rather than a current imbalance across a circuit.

And, given what we know about typical 'normal' earth currents in residential installations due to dodgy neutral connections, etc, these days, it's no wonder they were renowned for tripping for no apparent reason.

They did indeed. Also, if lightning struck aerial cables in the vicinity it would trip all the ELCBs in the area. Bad luck if you were on holidays and had food in the deep freezer as people often did back then.

When I worked at Gladesville Hospital, all the cottages there were fitted with them.

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A valve a day keeps the transistor away...

QUOTE: "safety switch" craze

I'm speculating hospitals would not be so enamoured with the tide of RCD zealotry:
Can't imagine I.C.U., E.R., O.R. sections of hospital wanting them:
Could cost more lives than they save

Not only do they have them but they are more sensitive. A domestic/commercial RCD trips at 30mA fault current. One in a hospital trips at 10mA. They are right through, including ICU, Theatres, the lot. That's not the downside though. The downside is that Australian law requires that each one be tested annually.

Areas in hospitals are divided into two groups - Body-protected areas, where RCDs are fitted; and Cardiac-protected areas, where there is more stringent earthing requirements.

When an RCD trips in a critical area such as an operating theatre a buzzer will sound to warn medical staff. Don't worry though, all important equipment that is attached to the patient has a built-in UPS. This includes all anaesthetic and life support systems, and also the surgeons lights.

It's not uncommon for a modern operating theatre to have upwards of 15 RCDs scattered around the walls.

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A valve a day keeps the transistor away...

all important equipment that is attached to the patient has a built-in UPS

Out of interest, what's the battery replacement regime for those UPS units?

I think the batteries that are in medical equipment is replaced every two years. I am not sure of the requirements there. They are mostly lead-acid gel types, similar to burglar alarms.

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A valve a day keeps the transistor away...

I had no idea! The electrical complexity of the modern hospital is impressive -- and costly!

A plug (no pun intended) for RCDs.....

Back in the 80s we used to modify colour TVs for video and audio in and out capabilities. Thousands of them.

All was going well until a new version of the TV appeared with no mains transformer. Operator unpacks the first one, fits the mod kit, plugs it in to test it.

Zappo! So much damage done that the brand new TV was a write-off.

Factory manager did something he should have done earlier and fitted an RCD to the overhead test power rails.

Mains transformers had to be fitted to all that model from then on.

Same thing happened again a few times after that, when the fitting of the mains transformer was overlooked by an operator, but no damage was done to the TV (or the operator!).. Apart from the undoubted safety angle it saved us a lot of money.

Healthcare engineering departments manage more compliance issues now than actual maintenance work. The paperwork is horrendous. Some of the regulations that have come into place in the last few years are just stupid. Some of you may have heard of the "range switch", where a stove in a domestic installation must have an isolation switch installed close by so the stove can be worked on without the serviceman going to the switchboard.

Well, the Australian Standard governing hospital electrical installations in patient areas takes that to a new level. Anything connected to a GPO in a patient area where the GPO cannot be readily accessed must have an isolation switch above workbench height so the appliance can be turned off if it catches fire or experiences some other disastrous malady. Some examples include drug fridges, televisions and fridges in patient rooms. It's just costly excess in my opinion and it raises a new issue, given the quality of switchgear these days - the more connections in an installation, the less reliable it is.

There's already been a few cases of people turning these switches off because they think they are light switches and where this has lead to the destruction of thousands of dollars worth of drugs or patients not being able to work out why their television doesn't work. So the switches have had to be labelled - at further cost to hospitals, as if providing healthcare is not already expensive enough.

The committees that work towards the issue of upgraded Australian Standards justify their existence by one simple ideal - a new edition must be more stringent than the last, otherwise they think their job isn't done.

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A valve a day keeps the transistor away...

The committees that work towards the issue of upgraded Australian Standards justify their existence by one simple ideal - a new edition must be more stringent than the last,

And double the price. The cost of AS documents is outrageous. Yet another example of the disbenefit of privatisation.

I noticed that start happening with the standards body becoming a backwater to their marketing enterprise, SAI Global.

I think I paid about $33.00 for my first edition of the SAA Wiring Rules back in the late 1980s. It's more than $250.00 now.

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A valve a day keeps the transistor away...

Privatisation has become one of the greatest public frauds ever & the benefits absolutely lied about.

Love the Isolation switch here for the stove. In a corner & damn near inaccessible. At least the house fuse box is a sub board & is actually in the laundry, which is a high traffic area (virtually an adjunct to the hallway, which it "T's" off of).

A documentary recently was on the running of a UK hospital including maintenance of the technical kit. One piece of kit was a steriliser for killing all of the infectious agents in a ward. It consisted of a machine that produced a fog of hydrogen peroxide intended to penetrate every nook and cranny. The consequences for electrical equipment sound dire, but there must be solution as I can't be the first person to think of it as a reaction product of hydrogen peroxide can be water.