safety switches in house

[dsurin66]

'The wife' was watching tabloid tv program and told me about a pregnant women who was tragically killed due to electrocution from the washing machine. The reporter was talking about the importance of having a 'ground connection'. Are they talking about a safety switch?

When we purchased our high class 25,000 baht washing machine it came with a plastic thing that the washing machine sits on. Its about 2 to 3 inches thick. Is the purpose of that a 'ground connection"? Or are we best to have an electrician install safety switches on the power point where the washing machine plugs into?

What other appliances should we install a safety switch for? Theres one outside the bathroom door which I presume is for the hot water shower system. I still wear rubber thongs in the shower everyday...

I presume the air con system doesnt need one as we obviously use the remote?

Thanks for your opinions on this

[sappersrest]

This is a very important question, and while many of us on the forum can give the answers,I feel that this question should be answered and explained by a qualified electrician.This will help the op and others come to terms that non grounded appliance , pose a very severe risk to life,and how to eleviate that risk.

[Pib]

That plastic thingie is just a pretty thingie primarily to raise the machine a few inches above the floor to keep it above any water that may be on the floor. It's common in Thailand for washing machine to be placed outside the residence under a roofed area....an area that can still see rain water blown in from the sides, a person who just washes down the area with a water hose, and/or just drains the machines wash water in that covered area. I guess a person could say it adds a small amount of safety but it mostly to keep the bottom portion of the washer out of water to keep it from rusting. Many refrigerators commonly come with the plastics stand also. It can even help to keep snakes and other critters from getting into the underside of the applicance machine.

Having a "ground" wire (safety ground wire) is a three wire hookup where you have the Live/Line (i.e., the 220 volts) and Neutral wire carrying the voltage to power the machine and then a safety ground wire (that third wire) that is connected from the case of the appliance to ground....that way if any of the 220V leaks to the case which a person will be touching, the majority of the current/amps is shorted to ground versus through the person's body which electrocutes them.

But just having a safety ground is not always enough to keep you from getting electrocuted...that's where a Residual Current Device (RCD) (also called other things like a RCBO, ELCB, etc) comes into play to quickly, within milliseconds, to shut off all voltage/current flow to the appliance when it detects current/amps flow occurring to the safety ground, through a person's body, just not flowing between the Live and Neutral wires where it's only suppose to flow. Basically it's acting as a switch to kill power to the appliance within milliseconds...quick enough to stop the current/amps flow through the person's body before it electrocutes them or maybe even before they feel anything...maybe not even feel a tingle of voltage.

Don't confuse a RCD type switch/device with a standard Circuit Breaker that only kills power to the appliance when it exceeds so many "whole amps"...it's to protect the machine, not the person because it only takes a very lower level of current/amps to electrocute a person...in the 0.1 to 0.2 amps ballpark...typical circuit breakers trip at 10, 15, 20 and higher amps....hundreds of times the amount of current/amps needed to electrocute a person.

Here a little more info on RCDs: https://en.wikipedia.org/wiki/Residual-current_device

Edited September 17, 2015 by Pib

[Crossy]

In order to assist for starters please post photos of:-

• Your distribution box
• The washer plug
• The outlet you want to plug it in to
• The safety breaker associated with the water heater

It's easier to look at images than to get you to describe what you have.

Also download and print this document http://www.crossy.co.uk/Handy%20Files/groundwire.pdf

It's also quite clear that your electrical knowledge is close to zero (nothing wrong with that), so please don't start taking the lids of anything just yet.

Do you have a "known good" electrician that you can call on?

EDIT also are you renting or owning, house or condo? So we get an idea of just how much work we recommend, just "make safe" or a "proper job".

[lopburi3]

Will add that if you paid 25k for a washer it should have been installed with proper ground - but if that was not mentioned would have same doubts you now have. Please do as requested by Crossy - with good luck you are fine - but your wife is right to question this as in Thailand such precautions often are ignored - and the results can indeed be serious.

[RichCor]

Things I learn off the Internet:

A machine chassis earth-ground will generally have three purposes:

1. Keep the in-use chassis electrical static/leakage level at the same 'grounded potential' as all other nearby grounded appliances.
   
2. Act as a direct electrical path to Earth-Ground in case of electrical fault
   
3. Act as a signal to Ground-Fault equipment to trigger circuit shut-off

(1) Ground as a voltage stabilizer: Some devices can build-up an electrical current on the chassis when running. Static or other energy can be induced by use of electrical motors, running belts, fast moving dry air, etc. and Earth-Grounding these devices helps bleed-off or keep this energy from building up and discharging to sensitive electronics or zapping someone or something contacting the chassis.

(2) Electrical path faults can occur when movement or other materials are introduced into an electrical environment that wasn't expected. In these instances it is hoped that any electrical active energy gets shunted directly to an Earth-Ground path, and not potentially waiting for an unsuspecting person to complete the electrical circuit.

(3) This is probably the most important and the least implemented type of safety. A detection device located either at your CU / Circuit Breaker or on the device itself detect a power imbalance and immediately cuts power to the circuit, preventing continued energy discharge. This has already been described in PIBs post as a "Residual Current Device (RCD) (also called other things like a RCBO, ELCB, etc)". Very, very important!!

** It should also be noted that some electrical appliances are never grounded, even if they have a metal chassis. Toasters would be one example.
Also, some devices may convert or isolate the electrical energy and need to remain isolated from "bonding" to a common Earth-Ground.
You should read your device owners manual carefully and check all guidelines before adding an additional Earth-Ground to any device.

[bankruatsteve]

** It should also be noted that some electrical appliances are never grounded, even if they have a metal chassis. Toasters would be one example.

Also, some devices may convert or isolate the electrical energy and need to remain isolated from "bonding" to a common Earth-Ground.

You should read your device owners manual carefully and check all guidelines before adding an additional Earth-Ground to any device.

Perhaps in a hospital, but in domestic any class-1 device must be grounded - and toasters are usually class-1.

[lopburi3]

Indeed my Phillips pop up toaster and my local toaster oven both have grounded plugs attached by maker.

And an RCD does not rely on a ground (thank goodness) - what the ground should do is blow a circuit breaker or fuse before anyone contacts live current in case of a fault.

[RichCor]

<...>

And an RCD does not rely on a ground (thank goodness) - what the ground should do is blow a circuit breaker or fuse before anyone contacts live current in case of a fault.

I tried to be careful in the descriptive text:

"A detection device located either at your CU / Circuit Breaker or on the device itself detect a power imbalance and immediately cuts power to the circuit, preventing continued energy discharge."

That's the wonderful thing about a modern-day RCD. It doesn't rely on a Earth-Ground wired connection to function. It works by sensing an imbalance between LINE and NEUTRAL (if current takes any other path besides Line or Neutral) the device triggers instantaneously opening the circuit.

Even so, "wired" Earth-Ground fault path connections are preferable to a human-as Earth-Ground connection during a fault condition.

[Crossy]

Even so, "wired" Earth-Ground fault path connections are preferable to a human-as Earth-Ground connection during a fault condition.

Absolutely!

It is important to realise that the 30mA 'safe' current is a compromise between nuisance tripping and how many people die. The very young, very old, sick or otherwise weakened are much more susceptible to fatal shocks.

Also note that the RCD (GFI or whatever your country calls it) does not limit the current, it just detects it. Get hold of a live wire with wet hands and you will get a painful shock before the RCD opens, which hopefully occurs before you die.

[angy]

I noted that two years ago was easy to find normal safety breakers in all the shops, Whatsadoo Homework etc, and now only the big one in thai style is available. I don't know if the other kind disappeared because they put it out of thai rules or what else.

[Crossy]

I noted that two years ago was easy to find normal safety breakers in all the shops, Whatsadoo Homework etc, and now only the big one in thai style is available. I don't know if the other kind disappeared because they put it out of thai rules or what else.

I have no problem sourcing RCDs and RCBOs in DIN, plug-in (Square-D) and stand-alone formats in both 30mA and 10mA trip currents.

Find them in HomePro, MegaHome and my local electrical emporium.

Of course all have the big Safe-T-Cut front-end units as well.

[Pib]

I bought a Square D plug-in 30ma RCD about a month ago at small mom & pop hardware store here in Bangkok. Then became dissatisfied about a week later when I saw the same Square D in HomePro and Thai Watsuda for about 100 baht cheaper. Anyway, when I first bought some Square D RCDs around 3 to 4 years ago I had a hard time finding any 30ma Square D RCD and ended up buying some Squard D 10ma RCDs. And the prices are now lower than they were several years ago....maybe they are selling better and the price is coming down.