Electrical Help

[lopburi3]

Believe that switch below the RCBO is "bypass mode" so the "ON" means the RCBO is not in circuit and the "OFF" means it is protected. Not good language and label but as that seems to be how it works and there is nothing written on that block other than on/off and no bypass mode above suspect that is what it is. Most units sold here with multi sensitivity have a bypass mode to allow lights during troubleshooting for small leakage.

[bankruatsteve]

^ as long as there is a load on the circuit then a N-E connection will trip the RCD, so plug anything in that will cause a current, then plug in your short N-E plug.

Not going into polarity here.

I only use the right equipment, and personally would not recommend L-E shorts to the laymen

Just to point out that a 15W lamp (or any watt lamp) is not a "short".

Sorry perhaps I was not clear.

If you plug a 15w lamp into a circuit, then that will draw a current. If you plug in ANOTHER plug which has been shorted N-E, L-E whatever you like then in theory the RCD will trip.

Swaying off topic a bit... But, in the states - which seems to be same as "MEN" - N and E are equipotential so where would a leak occur between them? ie: why would even a shorted N/E cause RCD to trip?

[Forkinhades]

NEVER, EVER, EVER plug any form of short (even N-E) into a live outlet. Period!

Use a load or resistance of some sort (like a 15W lamp) so that if something is wrong the worst that happens is the lamp lights..

Forky, what happens if the outlet you intend plugging tour N-E short into has a L-N reversal?

quick answer the mcb trips

If you plug an extension lead in with 2 or more outlets, first you plug in the lamp to make sure it works, then if ok (light on) you plug your shorted plug in.

I have been qualified for 25 years, and have been doing testing and inspection for the last 15 years.

Guys you really need something like this to test your equipment http://www.fluke.com/fluke/m3en/Installation-Testers/Fluke-1653B-Multifunction-Installation-Tester.htm?PID=72323

This will tell you at what TIME the rcd is tripping at, which is the most important factor, and at what currents.

[Forkinhades]

^ as long as there is a load on the circuit then a N-E connection will trip the RCD, so plug anything in that will cause a current, then plug in your short N-E plug.

Not going into polarity here.

I only use the right equipment, and personally would not recommend L-E shorts to the laymen

Just to point out that a 15W lamp (or any watt lamp) is not a "short".

Sorry perhaps I was not clear.

If you plug a 15w lamp into a circuit, then that will draw a current. If you plug in ANOTHER plug which has been shorted N-E, L-E whatever you like then in theory the RCD will trip.

Swaying off topic a bit... But, in the states - which seems to be same as "MEN" - N and E are equipotential so where would a leak occur between them? ie: why would even a shorted N/E cause RCD to trip?

It is measured on the consumer side, and not the supply side

[Forkinhades]

^ Just to elaborate the RCD is 'monitoring' any possible imbalance on the consumer (load) side.

[Crossy]

Guys you really need something like this to test your equipment http://www.fluke.com/fluke/m3en/Installation-Testers/Fluke-1653B-Multifunction-Installation-Tester.htm?PID=72323

At a list price of GBP 1,259 + VAT it's a bit outside the range of most here.

I have an old Robin KTS1630 (16th Edition) tester which I bought for a couple of hundred quid a few years back.

TRUCE on the RCD / RCBO testing OK, Forky can do as he likes with his short, I'll use my tester or lamp.

EDIT Something like this is much more affordable http://www.test-equipment.com.au/socket-testers/socket-outlet-tester-with-rcd-earth-leakage-test but in order to work properly here it will need an adaptor that swaps L & N

Slegers do one "Slegers RCD Polarity & socket Outlet Tester" which has a lead where one could replace the plug, not found a price for that yet.

[Negita43]

Hey you guys

'So many men so many opinions' Blaise Pascal

I don't want you to fall out over a question I asked.

And while you two argue about L- E N- E etc. and how to test please remember.

All I want to know is:

1. From the info you have do you think the boxes are wired correctly?

2. Does the ON/OFF on the RCBO mean ON is Bypass and OFF is RCBO active (as Lopburi3 seems to confirm (thank you).

3. Finally as Crossy suddenly mentioned MEN, has he seen anything in the info I sent that suggests that is what I have.

Thank you all for trying to help me

[Forkinhades]

^

If one has a voltage tester, and went to the DB, and measured between live (any mcb load side) and earth, this will also make the rcd trip. If configured correctly.

[Forkinhades]

Hey you guys 'So many men so many opinions' Blaise Pascal I don't want you to fall out over a question I asked. And while you two argue about L- E N- E etc. and how to test please remember. All I want to know is: 1. From the info you have do you think the boxes are wired correctly? 2. Does the ON/OFF on the RCBO mean ON is Bypass and OFF is RCBO active (as Lopburi3 seems to confirm (thank you). 3. Finally as Crossy suddenly mentioned MEN, has he seen anything in the info I sent that suggests that is what I have. Thank you all for trying to help me

You need photos are the supply for that, so we can work out the characteristics.

[Forkinhades]

@ crossy > peace brother much respect.

Certainly made good a rather dull Friday morning

[Tywais]

^

If one has a voltage tester, and went to the DB, and measured between live (any mcb load side) and earth, this will also make the rcd trip. If configured correctly.

I don't follow. A voltage tester will normally have a minimum impedance of 10 MOhms and the rcd is set at 6 mA so impossible to trip using a meter. Unless you put it on current setting.

[Negita43]

Fork in Hades - I have a digital voltage tester - two questions:

1. I assume I set it to measure volts

2. What do you mean by 'DB'

[Tywais]

Fork in Hades - I have a digital voltage tester - two questions: 1. I assume I set it to measure volts 2. What do you mean by 'DB'

Distribution Board.

[Crossy]

Hey you guys 'So many men so many opinions' Blaise Pascal I don't want you to fall out over a question I asked. And while you two argue about L- E N- E etc. and how to test please remember. All I want to know is: 1. From the info you have do you think the boxes are wired correctly? 2. Does the ON/OFF on the RCBO mean ON is Bypass and OFF is RCBO active (as Lopburi3 seems to confirm (thank you). 3. Finally as Crossy suddenly mentioned MEN, has he seen anything in the info I sent that suggests that is what I have. Thank you all for trying to help me

1. Yes I think they are correct. Check my post #13

2. See 1. "Turning to those same instructions, item 6 says that with the RCBO switch 'on' it is in 'direct' (bypass) mode so the correct position of

this switch is 'off'"

3. From the images you have posted MEN does NOT appear to be connected. Whether the supply is configured as MEN is unknown. As it is you're connected TT and fully RCD protected, i.e. safe

[bankruatsteve]

Just to add, in MEN configuration, you would (with the box you have) see a wire connecting the Earth bar and the Neutral bar and it appears you do not. What seems strange to me though, is that 2nd box is not RCD protected (yah?) and also does not appear to have grounded circuits. Hmmm.

[Negita43]

Thank you everybody

I only asked crossy to confirm Q1 and Q2 because you said in that post#13 you would check with a Thai engineer as your Thai wasn't perfect (but I am sure 1000% better than mine!)

One final question:

When the test button is pressed it trips the main circuit breaker NOT the RCBO breaker so why does bypassing the RCBO stop the main breaker tripping with the test button???

[Forkinhades]

Fork in Hades - I have a digital voltage tester - two questions:1. I assume I set it to measure volts2. What do you mean by 'DB'

yes set it to volts, 230v range

[Forkinhades]

^

If one has a voltage tester, and went to the DB, and measured between live (any mcb load side) and earth, this will also make the rcd trip. If configured correctly.

I don't follow. A voltage tester will normally have a minimum impedance of 10 MOhms and the rcd is set at 6 mA so impossible to trip using a meter. Unless you put it on current setting.

10 k ohms

[Crossy]

^

If one has a voltage tester, and went to the DB, and measured between live (any mcb load side) and earth, this will also make the rcd trip. If configured correctly.

I don't follow. A voltage tester will normally have a minimum impedance of 10 MOhms and the rcd is set at 6 mA so impossible to trip using a meter. Unless you put it on current setting.

10 k ohms

That must be a really ancient tester Forky, 10k impedance on, say, the 300V range is 30 Ohms/Volt, even a 1960's AVO was 20,000 Ohms/Volt.

My cheap DMM from Tesco has a constant input impedance of 10M Ohms (on volts ranges).

EDIT Still waiting for my Thai chap to get back to me (I'm in India right now).

[Tywais]

Just looked it up and there is a difference between a volt meter and a volt tester. A volt tester has a lower impedance to eliminate 'ghost voltages'. They now have dual impedance meters with high/low selections. I've always used standard multimeters where the impedance are normally no less than 1Mohm but more often 10Mohm. My error in not knowing the difference.

Fluke

[Forkinhades]

Just looked it up and there is a difference between a volt meter and a volt tester. A volt tester has a lower impedance to eliminate 'ghost voltages'. They now have dual impedance meters with high/low selections. I've always used standard multimeters where the impedance are normally no less than 1Mohm but more often 10Mohm. My error in not knowing the difference.

Fluke

yes voltage tester, not meter

[Forkinhades]

slightly off topic

Fluke actually do have one voltage tester that WILL not trip the RCD, all others will.

[Crossy]

Good point about ghost voltages, I wasn't aware of the modern low impedance testers. I wonder what price-premium the manufacturers are asking for what is in effect a 10k resistor across the input

However, 99.9% of the chaps reading this will have a regular, cheapo, DMM which won't trip the RCD when measuring L-E.

[Negita43]

Bankruatsteve - the second box is grounded but it has one cable to the bar and the other earths are connected in the roof space above the box and this one cable connects them to the second box earthbar which is obscured in the photos by the other cables

Anybody have a view on my last post viz

When the test button is pressed it trips the main circuit breaker NOT the RCBO breaker so why does bypassing the RCBO stop the main breaker tripping with the test button??? Or am I just being stupid? I will take no answers as yes you are!!!

[bankruatsteve]

Bankruatsteve - the second box is grounded but it has one cable to the bar and the other earths are connected in the roof space above the box and this one cable connects them to the second box earthbar which is obscured in the photos by the other cables Anybody have a view on my last post viz When the test button is pressed it trips the main circuit breaker NOT the RCBO breaker so why does bypassing the RCBO stop the main breaker tripping with the test button??? Or am I just being stupid? I will take no answers as yes you are!!!

Sounds good for the 2nd box.

By "RCBO" are you referring to the unit that has that written on it? While I've never seen a configuration like yours before, I'm pretty sure that is the "RCD" part of the breaker so what you are referring to as the "main breaker" actually is the RCBO.

[Crossy]

UPDATE from my Thai engineer, translation of the two clauses in the instruction manual:-

Item 6, is the selection switch for type of current (On = direct current selected)

Item 9, is Line (Live) output from sub-breaker.

This confirms that "OFF" is the correct setting for the RCBO switch and that the busbar is correctly positioned at the top of the unit

He also commented that it's the worst instruction manual he's ever read.

[Negita43]

Thanks crossy

do you have any comment on my last post question?

viz When the test button is pressed it trips the main circuit breaker NOT the RCBO breaker so why does bypassing the RCBO stop the main breaker tripping with the test button???

[Crossy]

I'm not totally sure Negita but many of this type of configuration link all the incoming breakers together so one tripping pulls out the other, can you post a photo of it in the tripped position after the button has been pressed?

It's possible that bangkruatsteve has the answer in his last post.

Will you be able to do the light bulb (L-E) test?

[bankruatsteve]

Suggest you post a note near that switch for any future headscratchers looking at it: ON = RCD Disabled, OFF = RCD Enabled

[Forkinhades]

UPDATE from my Thai engineer, translation of the two clauses in the instruction manual:-

Item 6, is the selection switch for type of current (On = direct current selected)

Item 9, is Line (Live) output from sub-breaker.

This confirms that "OFF" is the correct setting for the RCBO switch and that the busbar is correctly positioned at the top of the unit

He also commented that it's the worst instruction manual he's ever read.

Agreed, (and will swallow my knob) upon further looking at the original diagram, I can see the switch, and the busbar cannot phyically be installed on the bottom. I am going to blame the archa on that, and Im sticking to it!

You really do need to do a proper test, to make sure everything is working ok, TBH I never trust them push button test on the rcd itself (could in fact just be a switch with no electronics inside)

Here is a picture of my testing plug which I must add that I only use for doing dead tests, to get r1rn readings, but that is another story!

Nevertheless it will work in tripping proving your RCD is functioning!