Why didn't the circuit breakers trip when I cut the extension cord??

[Crossy]

21 minutes ago, giddyup said:

He said if I want to spend about 7-8000 baht better to put in a W-OP2 Digital Phase Protector.

NO!!!

 

That unit does NOT that's NOT provide earth leakage. It is an under-voltage unit, handy but not what you want in this case.

 

 

 

[KittenKong]

On 2/12/2019 at 10:12 AM, Crossy said:

2,700 Baht from HomePro, probably cheaper from your local electrical man.

Where would the local man buy them from?

[giddyup]

12 minutes ago, bankruatsteve said:

Replacing individual breakers with RCBO can be problematic when "borrowed neutral".  I thought you were getting an electrician to replace the main breaker with RCBO?  Your concerns solved.  And, I recall you are on single phase power which makes the recommendation of a phase protector seem strange.

For some reason he was reluctant to do that even though he had a new one boxed with him. I must admit he was talking over my head most of the time.

[Fruit Trader]

16 minutes ago, bankruatsteve said:

Replacing individual breakers with RCBO can be problematic when "borrowed neutral".  I thought you were getting an electrician to replace the main breaker with RCBO?  Your concerns solved.  And, I recall you are on single phase power which makes the recommendation of a phase protector seem strange.

Indeed a strange recommendation considering this is a personal safety issue.

 

The W-OP2 is a single phase under/over voltage detection device from WIP electronics Thailand. Its is designed to cut a low current control circuit when the supply voltage go outside set parameters for set time period.

[giddyup]

6 minutes ago, Fruit Trader said:

Indeed a strange recommendation considering this is a personal safety issue.

 

The W-OP2 is a single phase under/over voltage detection device from WIP electronics Thailand. Its is designed to cut a low current control circuit when the supply voltage go outside set parameters for set time period.

I ended up being totally confused as to what steps to take, so I asked him what did he suggest, and basically he said leave everything as it is. He didn't want any money for his time spent, even though he was here for nearly an hour, checked all the outlets with a voltmeter, made sure all all the fuses were connected correctly, got up into the ceiling and inspected wiring etc. I did end up giving him a few hundred baht as I don't expect something for nothing.

Edited February 14, 2019 by giddyup

[VocalNeal]

FYI

 

https://www.safe-t-cut.com/ฝ่ายขาย/

[giddyup]

Just now, VocalNeal said:

FYI

 

https://www.safe-t-cut.com/ฝ่ายขาย/

Thank you.

[GarryP]

This thread has got me worried. I'll have to check what protection I have at home when I get back from work. I doubt there is an RCBO breaker in place, but you never know. The former owner might have done something, but highly unlikely.   

[bankruatsteve]

11 minutes ago, giddyup said:

I ended up being totally confused as to what steps to take, so I asked him what did he suggest, and basically he said leave everything as it is. He didn't want any money for his time spent, even though he was here for nearly an hour, checked all the outlets with a voltmeter, made sure all all the fuses were connected correctly, got up into the ceiling and inspected wiring etc. I did end up giving him a few hundred baht as I don't expect something for nothing.

He was possibly not comfortable dealing with the live feed.  That requires rubber boots, gloves, and a steady hand at minimum.  Maybe get somebody from the PEA to do it.

[giddyup]

Just now, bankruatsteve said:

He was possibly not comfortable dealing with the live feed.  That requires rubber boots, gloves, and a steady hand at minimum.  Maybe get somebody from the PEA to do it.

Do they have electricians available for something like that?

[Crossy]

3 minutes ago, giddyup said:

Do they have electricians available for something like that?

Many of the PEA/MEA chaps moonlight, you need to talk to the staff at your local office.

 

That said, a local sparks will likely pull the live at the meter (seal? what seal?) so he can work safely in your board. 

[bankruatsteve]

5 minutes ago, giddyup said:

Do they have electricians available for something like that?

Sure.  It is usually work done "on the side" though and probably get a "farang" price.

[millymoopoo]

What your showing are overload circuit breakers, not a safety switch (earth leakage circuit breaker-residual current device) as 'crossy' said you will need a safety switch and a qualified electrician to install it.

However, and it's a BIG however, these devices work off detecting an earth current, minuscule as it may be, they need an earth connection to detect it, anything connected to it needs a functioning earth connection (wire), if your machine or your extension lead or it's plugs have no earth wire/contact no matter how good or how many safety switches you have they won't work.

Remember this is Thailand with low or no electrical standards, 2 wire (no earth wire) extension leads are common, as are 2 pin plugs.

Basically if it's only got 2 wires or 2 pins, no safety switch will work.

General rule of thumb, make sure everything has 3 wires/contacts/pins....!

[giddyup]

1 minute ago, millymoopoo said:

What your showing are overload circuit breakers, not a safety switch (earth leakage circuit breaker-residual current device) as 'crossy' said you will need a safety switch and a qualified electrician to install it.

However, and it's a BIG however, these devices work off detecting an earth current, minuscule as it may be, they need an earth connection to detect it, anything connected to it needs a functioning earth connection (wire), if your machine or your extension lead or it's plugs have no earth wire/contact no matter how good or how many safety switches you have they won't work.

Remember this is Thailand with low or no electrical standards, 2 wire (no earth wire) extension leads are common, as are 2 pin plugs.

Basically if it's only got 2 wires or 2 pins, no safety switch will work.

General rule of thumb, make sure everything has 3 wires/contacts/pins....!

Nearly every electrical appliance in Thailand is 2 pin only, I know that both the mower and hedge cutter are only 2 pin, as is the extension cord. Perhaps that's why the guy thought it a waste of time to install any kind of safety cutout?

[bankruatsteve]

Jeez.  Circuit breakers protect wires.  RCD (RCBO and the like) protect people.  Contemporary RCDs do NOT need earth.

 

2-pin plugs indicate class-2 equipment (don't need ground).  EXCEPT it seems to be common practice to use Schuko plugs here which are also 2-pin but contain ground (if proper).  The caveat is that Schuko receptacles are not common here.  Go figure.

Edited February 14, 2019 by bankruatsteve

[giddyup]

2 minutes ago, bankruatsteve said:

Jeez.  Circuit breakers protect wires.  RCD (RCBO and the like) protect people.  Contemporary RCDs do NOT need earth.

I'm getting some conflicting info here.????

Edited February 14, 2019 by giddyup

[bankruatsteve]

11 minutes ago, giddyup said:

I'm getting some conflicting info here.????

Hoping you can discern bad "information" from good advise.  Just read Crossy's posts and you will be good.

[jkcjag]

On ‎2‎/‎12‎/‎2019 at 9:20 AM, giddyup said:

When I see sparks fly and a blue flash I consider that a short.

"The cord was almost severed and sparks flew" … indicates electricity jumping a gap between conductors, and in this case, from the description, POSSIBLY between a gap (because of a cut) in just one of the wires, which is not a short circuit between the live and neutral from the supply. Think of a spark plug in an engine...sparks are jumping the gap all the time...that's how it works to fire the gas...but it's not a "short". Hence there may be no reduction in load in the circuit (the current was still passing through the equipment), and therefore no increase in current through the circuit to trip the breaker. IF you were to somehow touch the 2 wires supplying the equipment together (having cut both live AND neutral wires resulting in them touching briefly or both touching the metal blade of the equipment at the same time), then there would be a "short" in the circuit and I would expect the breaker to trip.

[giddyup]

7 minutes ago, jkcjag said:

"The cord was almost severed and sparks flew" … indicates electricity jumping a gap between conductors, and in this case, from the description, POSSIBLY between a gap (because of a cut) in just one of the wires, which is not a short circuit between the live and neutral from the supply. Think of a spark plug in an engine...sparks are jumping the gap all the time...that's how it works to fire the gas...but it's not a "short". Hence there may be no reduction in load in the circuit (the current was still passing through the equipment), and therefore no increase in current through the circuit to trip the breaker. IF you were to somehow touch the 2 wires supplying the equipment together (having cut both live AND neutral wires resulting in them touching briefly or both touching the metal blade of the equipment at the same time), then there would be a "short" in the circuit and I would expect the breaker to trip.

No, just had a look, both wires were severed, only a piece of the outside plastic still intact.

[Sumarianson]

MCB's can be faulty too. They can be checked by a very good electrician but I would replace that MCB as it is easier and cheaper. If MCB's short many times then they should be replaced as they may become inaccurate or the terminals may weld together. In fact the reccomendation is to replace after a single short. No one does that however and I do not see the need to do that. 

I agree that an double pole RCD be fitted in place of of your breaker as it will ensure a greater level of safety on all circuits. You need to have an electrician do this as sometimes you may have circuits with leakage current or faults that the current system will not detect and a good electrician will be able to resolve those issues should they arise.

I am a fully qualified NICEIC electrical contractor and part P installer.

[VocalNeal]

I'm an instrument/automation guy so i will defer to Crossy on voltages more than 24. ????

 

I can only see one downside of a "normal" Safe-T-Cut and that is when you cut through the lead while holding a plastic hedge trimmer you would trip the whole house. If in fact you did actually caused any ground leakage current as the hedge trimmer is plastic.

Edited February 14, 2019 by VocalNeal

[giddyup]

3 minutes ago, VocalNeal said:

I'm an instrument/automation guy so i will defer to Crossy on voltages more than 24. ????

 

I can only see one downside of a "normal" Safe-T-Cut and that is when you cut through the lead while holding a plastic hedge trimmer you would trip the whole house. If in fact you did actually caused any ground leakage current as the hedge trimmer is plastic.

Surely that only means resetting the Safe-T-Cut? I guess if there was a short when the house was unoccupied all appliances like fridges would be turned off as well. What difference does it mean in the hedge trimmer being plastic?

Edited February 14, 2019 by giddyup

[bankruatsteve]

21 minutes ago, giddyup said:

Surely that only means resetting the Safe-T-Cut? I guess if there was a short when the house was unoccupied all appliances like fridges would be turned off as well. What difference does it mean in the hedge trimmer being plastic?

A short would not trip an RCD - just the over-current breaker.  Geckos/ants/bugs/dust getting into an outlet can/will trip an RCD and that is the caveat for making it the main breaker.  If feasible, it is best to put refrigerators/freezers on non-RCD protected circuits.

[MuuKondiao]

On 2/12/2019 at 9:20 AM, giddyup said:

When I see sparks fly and a blue flash I consider that a short.

I think you are wrong about that. A short circuit, by definition is a means for the current to go through a shorter route - not through the electrical motor or appliance it was circuiting through - and back to the source or to ground, which could be through the person cutting into the wires.

So, if the live wire was not cut then the current continued through the narrowed pathway, while some pieces of metal -  the sparks - flew elsewhere.

[bankruatsteve]

6 minutes ago, MuuKondiao said:

I think you are wrong about that. A short circuit, by definition is a means for the current to go through a shorter route - not through the electrical motor or appliance it was circuiting through - and back to the source or to ground, which could be through the person cutting into the wires.

So, if the live wire was not cut then the current continued through the narrowed pathway, while some pieces of metal -  the sparks - flew elsewhere.

I happen to agree that it was not a short - more likely arcing.  But, it doesn't matter.  The OP is concerned about safety when accidents like that occur.  Usually the breaker will trip but in this case it didn't for whatever reason.  The live wire is then hazardous, even deadly.  That is where RCD is needed to keep people safe from accidental contact of the exposed live.

[DUNROAMIN]

On 2/12/2019 at 9:25 AM, giddyup said:

No test button that I see.

Get rid of your existing board, they normally only trip when too many amps are drawn, not so good for quick shorts. When I first moved into my new house that was the first thing I got rid of. Bought myself a G Safe RCBO board and installed. It has a tester and variable amp selection for the RCBO. Proved its worth when I had a steel drop saw short out through the body of the saw, got a quick tingle through my hand and the RCBO cut the power in nano second, may have been worse without it. I also made sure that the house was fully earthed before installing the RCBO.

[bankruatsteve]

5 minutes ago, DUNROAMIN said:

Get rid of your existing board, they normally only trip when too many amps are drawn, not so good for quick shorts. When I first moved into my new house that was the first thing I got rid of. Bought myself a G Safe RCBO board and installed. It has a tester and variable amp selection for the RCBO. Proved its worth when I had a steel drop saw short out through the body of the saw, got a quick tingle through my hand and the RCBO cut the power in nano second, may have been worse without it. I also made sure that the house was fully earthed before installing the RCBO.

Whew.  There is nothing wrong with the OP's "board".  The advice is to add safety protection for earth faults by putting a RCBO as the main breaker.  AGAIN - RCD detect earth faults NOT shorts.

[simon43]

Quote

 

He handed me a pair of flip flops as said wear them.
 

 

 

Well, a reasonable suggestion actually, since flip-flops are typically made of rubber which is a bad conductor of electricity.

 

When I used to work on the live 3 phase electrical systems at my little hotels in Phuket, (I designed/installed the circuits), I always wore my best thick rubber trainers and stood on a rubber car mat, just in case...

Edited February 14, 2019 by simon43

[VocalNeal]

1 hour ago, giddyup said:

Surely that only means resetting the Safe-T-Cut? I guess if there was a short when the house was unoccupied all appliances like fridges would be turned off as well. What difference does it mean in the hedge trimmer being plastic?

Yep. Just reset the Safe-T-Cut. There should be no short if the house is unoccupied but...rats.....

 

Because the hedge trimmer was plastic (insulated) there was no way for the current to get to you and through you to the ground.

[giddyup]

5 minutes ago, VocalNeal said:

Yep. Just reset the Safe-T-Cut. There should be no short if the house is unoccupied but...rats.....

 

Because the hedge trimmer was plastic (insulated) there was no way for the current to get to you and through you to the ground.

Did have a problem with rats in the roof for a while but since I scattered numerous moth balls up there never heard another one.