Electrical Help

[Negita43]

Well I thought everything on the electrical front was OK BUT...... In my CU The trip has a test button and when I pressed it guess what NO TRIP... . However the RCBO appears to have an on off switch and when this is switched to 'off' the trip test works

I attach a couple of not very good pics of the CU.

The RCBO on/off switch is the black blob at the bottom to the left of where I have put RCBO switch yes/no??

Any opinions on this – is it as it should be or has my sparks got his wires crossed somewhere?

[Crossy]

Interesting, I would leave the on-off switch in the position where the test button works.

But please can you get some clearer photos so we can read what the writing on the units says.

[Negita43]

Thanks Crossy, I'll try to get some better pics tonight but it's very difficult the box is in a dark place and so the flash comes on and because the box is white it reflects the flash. If I turn the flash off then the exposure time is so long that my handshake gives a blurred image. Anyway I'll consult David Bailey (if you're old enough to know who he is/was - not sure is or was)and try to get you some good pics tonight.

[Forkinhades]

Sounds like a neutral fault,, indeed clearer pictures needed

[Daffy D]

Thanks Crossy, I'll try to get some better pics tonight but it's very difficult the box is in a dark place and so the flash comes on and because the box is white it reflects the flash. If I turn the flash off then the exposure time is so long that my handshake gives a blurred image. Anyway I'll consult David Bailey (if you're old enough to know who he is/was - not sure is or was)and try to get you some good pics tonight.

Stick some tissue paper over the flash or sticky tape over part of the flash to reduce the glare.

I remember David Baily

[lopburi3]

Being on the other side of the pond my memories of great photographers was Ansel Adams - and that may be even further back.

Do not believe your camera has enough light to autofocus so suspect even a flashlight shining on box might help to get it in focus better.

[Negita43]

Hi Crossy and forkinhades Here are some better pictures (I hope),

Crossy may recall that some time ago when we were discussing the electrics for my new house that I was going to install 2 CU units linked (one for the aircon (not protected ) and one for the rest (protected).

So attached photos of both units, Instruction manual for CKY unit (if you can call it that and if you can read Thai) and 1 page from the CEO unit( I believe I have the CSU model).

Hope this helps you help me.

PS sorry about the size of the files but I didn't want to reduce quality

[bankruatsteve]

What is your "Sensitivity Switch" selected on? (I can't see that) If it's full through then that might be your quandary. ie: select 10mA and then check.

[Negita43]

I'm pretty sure it's set to the minimum ie 6mA BUT I will double check.

[Forkinhades]

At first glance it looks like the busbar is at the top! It should be at the bottom!

OK just woke and need a cup of tea.....brb

[Forkinhades]

Yep the busbar is at the top, thus ineffect bypassing the RCBO, making it redundant. You will need to change. Not too difficult. You also seem to have 2 mcbs at the right end which the bar does not reach, make sure the bar is extended enough with the single cables looped across, just do at the bottom, what 'they' have done at the top.

The second DB looks fine

The white covered copper strip at the top needs to be on the bottom, and all your singles need to go at the top, straight swap like for like.

[Forkinhades]

Will also need a better picture of the last 'mcbs' as I think they might be links to the second DB, and looks like the 2nd DB is being supplied by a 16amp.

I recommend that you install a main RCD on the 2nd board, and loop the feed from the main terminals of the first one.

[Crossy]

OK, before we all panic, there are CUs with the BUS at the top (Square-D for example).

I think this is one of them but the instructions are not totally clear. The layout of the RCBO terminals and positioning of the N bar at the bottom suggests that a top BUS is required as does the labelling of the MCB terminals in instruction item 9.

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', supporting what the OP is seeing. I'll get one of my Thai engineers to confirm this, my Thai is not that good.

Can you see where the fat wires that feed the second (unprotected) CU are connected at the other end?

Good to see you have a whole house surge arrestor.

NOTE that the sensitivity setting of 6mA is the MOST sensitive, if you get random trips click it up one level.

[Negita43]

Thanks Fork in Hades (Is it hotter than Thailand?).

Typical eh I spend a lot of money to protect my circuits and the electrician bye passes it !!!!

The last two MCB type switches are for surge protection and I think the Bus Bar does not need to reach them as they have their own connection to live and neutral

[Forkinhades]

Point to note, that the first diagram shows the busbar at the bottom! (might be for aesthetics!)

Also the position of the MCBs would suggest a bottom busbar

TiT

If the busbar does go at the top, dosnt explain why the RCD is not working

There is a diagram on the front of the RCD, a closer look at that would be good

[Crossy]

Point to note, that the first diagram shows the busbar at the bottom!

They are the instructions for the CEO unit (the right hand one) which is bottom bus.

The CKY instructions (3rd image) show appliances being fed from the bottom of the MCBs.

[Negita43]

Thanks Crossy I will hold fire till I get your confirmation about the CU top or bottom bus and the on off switch

With regard to the second box feed the sparks tells me that the feed is supplied from the main feed but t'd off in the roof space above (and also the earth). I will try to check this Saturday when my 10 days of lovely holiday start (well I say holiday but of course what I mean is I won't go to my normal job BUT I will be working trying to finish my house so I can move in!!).

[Crossy]

You can do a quick and dirty check that your RCBO is actually protecting you.

Connect a 15W lamp to a 3 pin plug, but connect it between L and E, plug it in to an outlet and turn on. The RCBO should trip. If it doesn't first check that the outlet is wired correctly.

[Forkinhades]

^ a couple of edits to previous post

[Forkinhades]

You can do a quick and dirty check that your RCBO is actually protecting you.

Connect a 15W lamp to a 3 pin plug, but connect it between L and E, plug it in to an outlet and turn on. The RCBO should trip. If it doesn't first check that the outlet is wired correctly.

sorry but disagree with that as the mcb will trip, and be careful that lamp does not explode.

connect N-E together in a plugtop

[Crossy]

You can do a quick and dirty check that your RCBO is actually protecting you.

Connect a 15W lamp to a 3 pin plug, but connect it between L and E, plug it in to an outlet and turn on. The RCBO should trip. If it doesn't first check that the outlet is wired correctly.

sorry but disagree with that as the mcb will trip, and be careful that lamp does not explode.

connect N-E together in a plugtop

I was doing this for years before I got a proper RCD tester.

Why would the lamp explode? There can be no more than 220V L-E.

Why would the MCB trip? N and E are essentially the same connection anyway in a MEN system.

A N-E connection will not necessarily cause an RCBO trip, it MAY but it also MAY NOT so it's not a valid test.

[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

[Negita43]

Hi Crossy

I've just read your last post - just one question/observation

You mention MEN system - I didn't think I had a MEN system as you advised against it on the grounds of not being sure about reversed live and neutral before.

Does what I have sent you in the pics suggest MEN?

[Forkinhades]

^ seeing as you have asked crossy, I will let him answer, as I have the greatest respect

[Negita43]

Hi Fork in Hades

Please don't be upset. I value all the input I get.

I asked Crossy about MEN because he was the one who mentioned it in his post and he had posted to me about MEN before (3 or 4 months ago)

[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".

[Forkinhades]

Hi Fork in Hades

Please don't be upset. I value all the input I get.

I asked Crossy about MEN because he was the one who mentioned it in his post and he had posted to me about MEN before (3 or 4 months ago)

Totally not upset

[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.

[Crossy]

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?

[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