Elcb Extension Reel With 2 Core Cable

[BadtzBee]

Hi ThaiVisa members, 1st post ever after 3 years here.

A question for the electrically minded amongst you. I'll keep it brief.

The attached pics say it all, my question - <deleted>? Doesn't an Earth Leakage Protection Device need an earth ?

[Crossy]

An RCD / ELCB / GFI does not need a ground to function as it monitors the differential in current between the L and N conductors, if the differential exceeds the trip current of the RCD it opens.

That said, the unit you show accepts 3 pin plugs and so should include 3 core cable.

[BadtzBee]

Thanks for the (quick!) reply. Appreciated.

So, is it worth the expense to replace the 2 core cable with 3 core? Would I gain any appreciable safety benefit?

[Crossy]

So, is it worth the expense to replace the 2 core cable with 3 core? Would I gain any appreciable safety benefit?

If you use the lead with appliances that have 3 pin plugs then you need to provide a ground, if you only use double-insulated (2 pin) appliances then adding the extra wire will make no difference.

If you decide that you want to install a 3 core flex, take the reel apart first and make sure there is some way of connecting the ground wire to the ground pins in those outlets.

[electau]

An RCD will not prevent you from receiving an electric shock if there is an earth fault, however a 30mA RCD will disconnect the supply before fillabration of the heart occurs and in the case of 10mA units muscular contraction occurs. mA x time in mS.

One should point out that these extension leads with RCDs available in Thailand do not comply with IEC, BS or AS/NZ standards.

They appear to comply with Thai Industrial Standards (TIS). Most socket outlets are 2 pin not 3 pin.

[bankruatsteve]

Hope this not too off topic... Has anyone figured out why you can buy an extension reel (like the OP has) for (sometimes a LOT) less than just buying the cable?

And, just to suggest the OP decide if he should worry about ground: Make a list of all the equipment you might plug into that thing and then check if they 2 or 3 prong. I think you not likely to find many 3-prong so, like Crossy says, adding the ground won't help a bit. Maybe the real question is why you need the extension except for temporary connections?

[Pacificperson]

Fill the grounding holes with epoxy, then you will not be tempted to use three pin equipment.

[haveaniceday]

I know next to nothing about this subject, but, do note that it is a little misleading assuming that if it should have 3 pins it will. Many things in Thailand that would have 3 pins in Australia, only have 2 in Thailand, and expect you to know this and earth it from the back of the appliance. I have a brand name fridge and washing machine and water pump that have two pins.

Would you like your metal fridge earthed?

When you stick your hand in the washing machine water, and there is a issue, do you want to be the earth?

and 2 prongs on a steel water pump.......<deleted>?

All these things should be earthed as well, manually by you.

Edited November 21, 2011 by haveaniceday

[electau]

Earthing of equipment.

Exposed conductive parts.

The exposed conductive parts of electrical equipment shall be earthed where the electrical equipment is:-

Installed or could operate in an earthed situation; or not installed in an earthed situation but any exposed conductive parts of the electrical equipment is electrically continuous with an extraneous conductive part that is located in an earthed situation.

Earthed situation.

A situation where there is a reasonable chance of a person touching exposed conductive parts and, at the same time, coming into contact with earth or any conducting medium that may be in electrical contact with the earth or through a circuit may be completed to earth.

Within 2.5metres in any direction from a conductive floor (such as an earthen, concrete, tile or brickwork flooring) permanently damp surface, metallic conduit or pipe, metal cable sheath or armour or any other material or which a person may stand.

Ref AS3000.

The above should explain where earthing is required in normal wiring practice within an electrical installation.

Edited November 21, 2011 by electau

[Crossy]

Electau, you need to translate that into 'Average Joe', sadly AS3000 suffers from the same issues as BS7671, they talk in ways that are very open to interpretation. Those paragraphs you quote are difficult for me to interpret and I know what they mean at least in a UK context.

Havaniceday, don't forget, there are metal cased appliances that are also double-insulated and do not require a ground wire. My Toshiba fridge has a 2 pin lead, a metal case and the double-insulated symbol hidden round the back.

Looks like this:-

My take is simply, if it has a 3 pin plug it definitely needs an earth, if it doesn't then it may need an earth.

[wimpy]

The power supply for my Toshiba laptop came with a three prong plug, but there are only two wire connected to it.

[Crossy]

The power supply for my Toshiba laptop came with a three prong plug, but there are only two wire connected to it.

OK, OK, an exception

But it will do no harm to earth the unconnected pin whereas leaving a functional earth pin unconnected is potentially hazardous.

[electau]

Electau, you need to translate that into 'Average Joe', sadly AS3000 suffers from the same issues as BS7671, they talk in ways that are very open to interpretation. Those paragraphs you quote are difficult for me to interpret and I know what they mean at least in a UK context.

Havaniceday, don't forget, there are metal cased appliances that are also double-insulated and do not require a ground wire. My Toshiba fridge has a 2 pin lead, a metal case and the double-insulated symbol hidden round the back.

Looks like this:-

The interpretation is very clear, earthing of electrical equipment is required, as if one does a risk assessment and asks the question "is it in an earthed situation" the answer must be "yes" Class 2 double insulated equipment is not earthed. Class 1 must be earthed. AS3000 is written so that it avoids different interpretations.

If your house has conductive floors and walls you have an earthed situation.

However in Thailand RCDs are regarded as sufficient protection where there is no earthing.

Edited November 22, 2011 by electau

[BadtzBee]

Thanks for all the input everyone. (input - ho ho )

Originally I bought the extension after observing the safety procedures (sic) being employed by the workers building my house. I'm sure many who have built here know

what I'm talking about - bare wires inserted into 10 baht two pin sockets conected to a 100 amp knife switch nailed onto a tree in a pool of water to run any and all equipment, the welder earthed with a length of rebar to anywhere handy etc etc.

Now the house is completed, I use the reel to run the twintub downstairs, and the occasional power drill or grinder. As Bankruasteve suggested, not many items have three pins anyway, so no big deal.

I might have a closer look (thanks Crossy) to see if it's viable to replace the 2 core with 3 anyway - can't hurt the wallet too much, or maybe find an earthed extension reel (as Bankruasteve implies, it is probably cheaper than buying the cable on its own)

Cheers, B

[bankruatsteve]

Not sure what a twintub is - but if you have a continuous use, you might consider putting in a dedicated line to it (can break off from one of your protected circuits). The drill and grinder should be double insulated so adding a ground for those probably superflluous. The only problem you might have now is running out of projects.

[BadtzBee]

[BadtzBee]

Oops - edit double post

Edited November 22, 2011 by BadtzBee

[BadtzBee]

"Not sure what a twintub is - but if you have a continuous use, you might consider putting in a dedicated line "

Yeah, cos no-one ever has enough 'projects' going on after just moving into their new house . I'll get on it right away....

Cheers, B