Trusted Sparky Required

[tuky]

I have no faith whatsoever in the electrical wiring in my 9 month old house.

Every month we have break downs, shorts etc.

My wife and her family do not have any respect for electricity and the damage it can cause a human. Luckily we have a safe-t-cut which I believe has probably already saved a life, perhaps even my little daughters.

When the safe-t-cut trips my Father in law just turns the tolerance up, I turn it down again and get yelled at because it keeps on tripping, obviously I am a stupid farang because what I do makes it trip, but what the father in law does stops it tripping. HELP.

I really need a qualified, trustworthy sparky to come and perform a full elctrical safety test, and then make any changes required to get the electrical system up to a safe standard.

Does anybody know someone they can recommend?

[penzman]

I've told my wife to ask one of the electricians from her factory to come and fix our problem with the clothes drier which keeps tripping a breaker.

I'll let you know if one drops by and if he's interested.

[tuky]

Thanks mate. Scary isn't it?

[chownah]

Thanks mate. Scary isn't it?

<{POST_SNAPBACK}>

I've never had a safe-t-cut with a variable sensitivity. How do you know if they are set too sensitive?.....how do you decide when to adjust them?

[tuky]

AFAIK you cannot set it too sensative as there should be 0 earth leakage (in a perfect world). But the safe-t-cut I have has a 5-30 mA stepped setting control at a trip speed of 0.3 +/- 0.02 seconds.

[Eric Davis]

PM Jockstar,he's a sparky.

[tuky]

Thanks Eric

[Jai Dee]

PM Jockstar,he's a sparky.

Better lock up your fridge though... he'll drink it dry...

[chownah]

AFAIK you cannot set it too sensative as there should be 0 earth leakage (in a perfect world). But the safe-t-cut I have has a 5-30 mA stepped setting control at a trip speed of 0.3 +/- 0.02 seconds.

<{POST_SNAPBACK}>

I'm wanting to learn more. If they can't be set too sensitive then why do they have an adjustment for this? Even at its most insensitive it will trip when the imbalance is only 30 mA....thats 0.03 of one amp....this is a very very small current...I'm not trying to give an answer here...I'm just wondering about this stuff and how it works. In the US they have GFI's which means 'ground fault interrupt'....I think these are the same as a safe-t-cut....all the ones I've seen in the US are not adjustable...but then these are small units used for only one circuit ...the ones in Thailand I've seen have an amp capacity to handle many circuits...mai kowchai!!!

Anyway, when in doubt on this stuff it is clearly best to check it out!!!

[Crossy]

AFAIK you cannot set it too sensative as there should be 0 earth leakage (in a perfect world). But the safe-t-cut I have has a 5-30 mA stepped setting control at a trip speed of 0.3 +/- 0.02 seconds.

I'm wanting to learn more. If they can't be set too sensitive then why do they have an adjustment for this? Even at its most insensitive it will trip when the imbalance is only 30 mA....thats 0.03 of one amp....this is a very very small current...I'm not trying to give an answer here...I'm just wondering about this stuff and how it works. In the US they have GFI's which means 'ground fault interrupt'....I think these are the same as a safe-t-cut....all the ones I've seen in the US are not adjustable...but then these are small units used for only one circuit ...the ones in Thailand I've seen have an amp capacity to handle many circuits...mai kowchai!!!

Anyway, when in doubt on this stuff it is clearly best to check it out!!!

Cross-body lethal current is generally accepted to be 10mA, so your 30mA RCCB will kill you before it trips (or certainly give you a nasty surprise)

The idea of the GFI / RCD / RCCB / Safe-t-Cut (all are basically the same thing) is to kill the power in the event of a ground fault before someone touches a live surface.

Some appliances are naturally 'leaky' (desktop PCs for example) so an adjustable unit is a nice idea, adjust it so it just doen't trip under normal circumstances then if you do get a fault it will drop out before it cooks someone.

Edited September 14, 2005 by Crossy

[Pink Mist]

can you afford an air fare and expenses Reith, I canfix it for you as you know

up to you

am in Darwin at the moment so very close

[lopburi3]

The reason for Safe-T-Cut adjustment is to allow for the normal leakage found in most homes - the idea is to set it as low as you can without frequent trips that you can not find. To continue to provide safety the max is what most other units use as normal (30ma). If you normally run at 5ma and it starts to trip you can set it to 10 or higher until you can find and correct the problem. This helps to alert you to pending problems before you have to make the choice between no protection or no power.

[lopburi3]

Cross-body lethal current is generally accepted to be 10mA, so your 30mA RCCB will kill you before it trips (or certainly give you a nasty surprise)

I believe you will find 30ma is the normal trip for personal safety - a much higher unit is available for fire safety. You should survive 30ma (I have done it many times).

[Pink Mist]

a bit of free advice, dont worry about leakage there should be none, check the integrity of the wiring of the installation, minimum 2 Meg but in reality it should be infinity in a new installation, start there and work back, remove all appliances and devices from same and work your way thru, I just did my testing course again while at roxby so we are talkin to AS 3000 standards

[RCP]

Okay,1st ,you can do a simple check for the time being until you get an electrician , Unplug 1 electrical item at a time or open 1 breaker at a time .Until it quits tripping.

[tuky]

Well, I am not actually there at the moment so this is why I am looking for someone else to do it. My wife tells me it trips each time she turns the hotwater on, so it is probably a stuffed coil in the heater, although I thought the little leccy heater had it's own RCD.

That is this time. Last time it was the water pump that runs off an external GPO, they had spliced the outdoor lights off this GPO and twist terminated the two legs, + and - legs had melted the insulation and were shorting. They lived without the whole downstairs GPO circuits for almost a week before anyone thought to get someone in to fix it (and no water pressure)

I will be home soon, so perhaps I should just cross my fingers until I get there with a megger and a multimeter and then check each loop myself.

I never have found the earth stake either.

[Pink Mist]

Reith smack youself around the head mate treat it as though you were testing to AS 3000, a new installation shouldnt have any probs with insulation NEVER unless we have cowboys, then you gotta find the prob

as you aint gonna pay my air fare and py expenses, just remember I am close

[lopburi3]

Well, I am not actually there at the moment so this is why I am looking for someone else to do it. My wife tells me it trips each time she turns the hotwater on, so it is probably a stuffed coil in the heater, although I thought the little leccy heater had it's own RCD.

That is this time. Last time it was the water pump that runs off an external GPO, they had spliced the outdoor lights off this GPO and twist terminated the two legs, + and - legs had melted the insulation and were shorting. They lived without the whole downstairs GPO circuits for almost a week before anyone thought to get someone in to fix it (and no water pressure)

I will be home soon, so perhaps I should just cross my fingers until I get there with a megger and a multimeter and then check each loop myself.

I never have found the earth stake either.

<{POST_SNAPBACK}>

The Safe-T-Cut is probably set more sensitive than the built in GFI of the water heater (you are talking about a shower unit I believe). They should turn that unit off until you can check it out as they are extremely dangerous if there is any fault. You want to make very sure there is a real ground installed (use that meter to make sure full voltage between hot and ground/chaises. There should be a test button on unit and that should be exercised at least monthly. You may want to just change it out if more than a couple of years old. But you can use the meter to check it out - just remember that you may not see the cause until there is water pressure to activate the heating unit so a little hard to trouble-shoot.

Edited September 14, 2005 by lopburi3

[Pink Mist]

As a qualified electrician I can only reinforce my original advice, re attach devices as you can prove they work

[samran]

Get your father in law to test all the sockets by sticking a metal fork into each one.

That’ll fix the real problem

[tuky]

All is now well. We found a "jack of all trades" and he pretty much rewired the joint, built a biological filter and made improvements to the waterfall, added a fountain and lights in our fishpond, is building some gates to keep our daughter inside the outdoor eating area, built a stainless cover for our (full) underground water storage tank, is going to quote us on fixing several leaks in the roof, wants to quotes us on building a swimming pool and outside storage/pool room.

He actually did a great job and I can recommend him, he speaks reasonable english. However from the looks of things he will not be finished at our house until after the new airport is up and running .

[chownah]

How was the 'biological filter' constructed? Is this a slow sand filter?

[tuky]

chownah, the water is pumped over a filter (white cotton like substance) and then it comes up through a kind of gravel and then onto the waterfall.

Similar to the diagram below

[elkangorito]

It appears that some points have been slightly overlooked.

Firstly, before anyone thinks that they need an RCD, which is a band-aid, the real problem must be addressed.

Earthing & general electrical safety in Thailand is, at best, attrocious & potentially lethal.

Firstly, for the earthing system to work effectively, the "star point" of the distribution transformer (usually the transformer on a pole near your house that also supplies many other residences) must be effectively earthed at its location.

Secondly, your home must have a main earth. This is usually a copper sheathed steel pole about 1-1.5m long, which is driven into the ground until about 200-300mm is still above ground. A pure copper rod is not ideal as it may bend if you are driving into hard ground. Also, it is NOT true that you must "reach the water table" in order for the earthing system to be effective. Soil has quite a high moisture content at about +600mm below the surface, which is sufficient to maintain an acceptably low earth loop impedance. The earth cable attached to the earth rod must be electrically bonded to the rod by way of a metallic clamp specifically designed for such a purpose. The earth cable must be the same size as the main neutral conductor (about half size of any phase conductor). Eg, if the supply phase conductors are 10mm squared, the acceptable earth cable size is minimum 4mm squared. This clamp must then be painted with acrylic paint to minimise the effect of oxidisation.

Thirdly, you must only have ONE (1) main distribution board (DB) in your home, from which sub boards are supplied with electricity. At this main DB, an MEN link must be made. This is achieved by connecting the main earth bar, which has now been effectively earthed by the earth stake, to the main neutral bar with appropriately sized cable.

Please note that this form of earth protection is not very effective unless the distribution transformers' "star point" is effectively earthed as well as the residence being effectively earthed, as previously described.

This system of earthing is called the "MEN System of Earthing". THE INSTALLATION OF THE MEN LINK IS CRUCIAL TO THE SAFETY OF AN ELECTRICAL INSTALLATION.

The MEN System is the best form of earth protection. RCD's are electronic devices that can fail at any given time, can be adjusted incorrectly & most do not detect earth faults of non-sinusoidal waveforms, for example, a hair dryer in a bathroom, which uses diode rectification to reduce fan speed & heat output. Many people die from hair dryers for exactly this reason.

RCD's should be treated as "secondary" earth protection (MEN is "primary"). Ideally, they should be set at about 30mA, which is adequate for personal protection. It has been previously stated that setting these devices at 30mA will not save your life because all it takes is 10 mA through the heart to kill you. NOT TRUE. Most dry human skin has high resistance, which therefore reduces the current to well below 10mA. Also, the "tripping speed" of the circuit breaker in the RCD also plays a big part of saving your life. RCD's should not be installed on such power circuits supplying devices that use electric motors (refrigerators), electronic speed control, switch mode power supplies (computers). Electric motors have a "standing residual leakage current", which increases as the device gets older. Electronic speed controllers & computer power supplies produce harmonic wave forms, which can render the RCD's inoperable (this scenario is very rare).

Last but not least, before power is applied to the complete installation, it should be "insulation tested" or "Megger tested". That is, the insulation resistance of the wiring is tested whilst in open circuit condition. Ideally, this resistance should be very close to infinity. If any device, excluding heating elements & the like, are below 2 megohms resistance, the device is deemed as dangerous & should be repaired or discarded.

SUMMARY.

Make sure an MEN Earthing System is installed into your house & all non-"double insulated" devices are earthed effectively through a 3 pin wall plug & socket.

Use RCD's only as a secondary measure as they are less reliable than the MEN system.

[chang35baht]

It appears that some points have been slightly overlooked.

Firstly, before anyone thinks that they need an RCD, which is a band-aid, the real problem must be addressed.

Earthing & general electrical safety in Thailand is, at best, attrocious & potentially lethal.

Firstly, for the earthing system to work effectively, the "star point" of the distribution transformer (usually the transformer on a pole near your house that also supplies many other residences) must be effectively earthed at its location.

Secondly, your home must have a main earth. This is usually a copper sheathed steel pole about 1-1.5m long, which is driven into the ground until about 200-300mm is still above ground. A pure copper rod is not ideal as it may bend if you are driving into hard ground. Also, it is NOT true that you must "reach the water table" in order for the earthing system to be effective. Soil has quite a high moisture content at about +600mm below the surface, which is sufficient to maintain an acceptably low earth loop impedance. The earth cable attached to the earth rod must be electrically bonded to the rod by way of a metallic clamp specifically designed for such a purpose. The earth cable must be the same size as the main neutral conductor (about half size of any phase conductor). Eg, if the supply phase conductors are 10mm squared, the acceptable earth cable size is minimum 4mm squared. This clamp must then be painted with acrylic paint to minimise the effect of oxidisation.

Thirdly, you must only have ONE (1) main distribution board (DB) in your home, from which sub boards are supplied with electricity. At this main DB, an MEN link must be made. This is achieved by connecting the main earth bar, which has now been effectively earthed by the earth stake, to the main neutral bar with appropriately sized cable.

Please note that this form of earth protection is not very effective unless the distribution transformers' "star point" is effectively earthed as well as the residence being effectively earthed, as previously described.

This system of earthing is called the "MEN System of Earthing". THE INSTALLATION OF THE MEN LINK IS CRUCIAL TO THE SAFETY OF AN ELECTRICAL INSTALLATION.

The MEN System is the best form of earth protection. RCD's are electronic devices that can fail at any given time, can be adjusted incorrectly & most do not detect earth faults of non-sinusoidal waveforms, for example, a hair dryer in a bathroom, which uses diode rectification to reduce fan speed & heat output. Many people die from hair dryers for exactly this reason.

RCD's should be treated as "secondary" earth protection (MEN is "primary"). Ideally, they should be set at about 30mA, which is adequate for personal protection. It has been previously stated that setting these devices at 30mA will not save your life because all it takes is 10 mA through the heart to kill you. NOT TRUE. Most dry human skin has high resistance, which therefore reduces the current to well below 10mA. Also, the "tripping speed" of the circuit breaker in the RCD also plays a big part of saving your life. RCD's should not be installed on such power circuits supplying devices that use electric motors (refrigerators), electronic speed control, switch mode power supplies (computers). Electric motors have a "standing residual leakage current", which increases as the device gets older. Electronic speed controllers & computer power supplies produce harmonic wave forms, which can render the RCD's inoperable (this scenario is very rare).

Last but not least, before power is applied to the complete installation, it should be "insulation tested" or "Megger tested". That is, the insulation resistance of the wiring is tested whilst in open circuit condition. Ideally, this resistance should be very close to infinity. If any device, excluding heating elements & the like, are below 2 megohms resistance, the device is deemed as dangerous & should be repaired or discarded.

SUMMARY.

Make sure an MEN Earthing System is installed into your house & all non-"double insulated" devices are earthed effectively through a 3 pin wall plug & socket.

Use RCD's only as a secondary measure as they are less reliable than the MEN system.

<{POST_SNAPBACK}>

Firstly: I would like to ask you Envangelisto If I am using my diodically rectified hair drier in my sitting room am I putting my self at risk sinusoidally?

Secondly: my electric shower hs an earth wire coming from the shower, going out thru the mesh screen in the bathroom, trailing down from upstairs and stops short by about 1 inch(2.54CM) from the large concrete jar in which my wife keeps her lovely angel fish and some guppies discreetely concealed under some rather attractive lillypads. Am I right in thinking that I have an excellent earth because I can see the electricity arcing from the cable to the water in the jar? Much like lightning bolts!

Thirdly: Is this good for the Guppies?

[elkangorito]

<{POST_SNAPBACK}>

Firstly: I would like to ask you Envangelisto If I am using my diodically rectified hair drier in my sitting room am I putting my self at risk sinusoidally?

Secondly: my electric shower hs an earth wire coming from the shower, going out thru the mesh screen in the bathroom, trailing down from upstairs and stops short by about 1 inch(2.54CM) from the large concrete jar in which my wife keeps her lovely angel fish and some guppies discreetely concealed under some rather attractive lillypads. Am I right in thinking that I have an excellent earth because I can see the electricity arcing from the cable to the water in the jar? Much like lightning bolts!

Thirdly: Is this good for the Guppies?

<{POST_SNAPBACK}>

Firstly, sinusoidally speaking, ensure that you are sitting on an obloid spheroid & not on your haemorrhoids.

Secondly, sell the rare item you have for millions of baht...the "concrete jar". It is the only one in the whole cosmos. Also, be careful! Concealling guppies under attractive lillypads may be an offense in this country.

Thirdly, the guppy earthing system is easily able to cope with lightning but only if they are male (MEN).

Loved your comeback