Is our electrical system safe? RCDs / RCBO

[bbabythai]

I read this thread and didnt fully understand the technical side of things:

 

 

Photos attached of our new set up. We have renovated a building for a medical clinic and have breakers everywhere (not included in the photos). 

 

The question is... by looking at the photos have they set up safe RCDs / RCBO correctly? I have no background in this and dont fully understand the requirements. 

 

I watched the guy cut a hole in the concrete and set up the 'earth' thing. Then he laid concrete over it. Thus I know earth safety is installed

 

Any opinions are appreciated. Im mindful of the fact that TIT and that even though the red cover mentions RCBO. How do I know if the guy has installed it correctly?

 

Finally, a small issue is that this morning some workers were using a welding machine out the front and the power cut to the whole ground floor. The electrician told us he would have to increase the amp. Is this the solution. I noticed a room out the back where our running machine has the same prob. ie. the lights often dont work. Is this a low amp issue?

thanks

[bankruatsteve]

Hospitals and medical centers in the states have a different set of code rules that apply (versus domestic and industrial).  I don't know what they are or if the same in Thailand so just to say that might be something to research.

 

The ground rod should not have been covered up.

 

"More amps" could mean over-sizing a breaker or something else stupid.  Your lights would not be having an issue from "low amps".  Could be a loose connection somewhere - if you get an "electric smell" - that's probably it.

 

Welders have habit of dialing up the amps more than needed but should hook into at least a 20 amp breaker with nothing else in use.

 

The experts will probably have more to say.

[ardsong]

The hook up should normally be:

- from the public net, cables to the Safe-t-Cut box

- cables from Safe-t-cut to the distribution box with overamp protection switches.

- both boxes should be connected to ground, where the grounding should be thorough, i.e. a thick cable to a copper rod that sits deep into the soil.

 

the 2nd picture above, does not ring a bell to me what that is, normally there is a protection plate which hides the wires and allows only the switches to touch, hope that you removed that plate only for this photo and connecting wires are not in touching range!!!

it looks  like the breakers are in serie to one off take, while there is a paralle off take as well. ???

[Crossy]

An off-topic post has been removed.

[Crossy]

Can you post an overall photo of the arrangement, particularly where in all this the Safe-T-Cut is located.

[Crossy]

From the limited information we have thus far I'm seeing.

 

A 100A 3-phase incomer (MCCB) correctly linked for MEN with the neutral going via the ground bar. I'm a little concerned at a potentially undersized neutral link ground to neutral bar, looks like 10mm², should be at least 16mm².

 

Two sub-boards, one fed directly from the incoming MCCB (no earth leakage protection) second sub fed from a 63A MCCB via a 63A 3-phase Safe-T-Cut.

 

One of the boards has a 3-phase 32A breaker for the x-ray machine. Can't tell which at present.

 

There also appears to be a feed taken from the incoming supply to some sort of mains monitoring (thin wires). These wires will vaporise in a flash (figuratively and literally) if something goes awry at the far end, not good.

[Led Lolly Yellow Lolly]

There is a serious arc flash danger there with those improvised bus bars, personally I would condemn the installation on that point alone.

[Crossy]

6 hours ago, NilSS said:

There is a serious arc flash danger there with those improvised bus bars, personally I would condemn the installation on that point alone.

I agree, there's no reason for them. It's no real issue putting two ring-crimps on each outgoing bolt of the incoming MCCB.

 

I really (really, really) hope there's a cover over that lot.

[Led Lolly Yellow Lolly]

I watched the guy cut a hole in the concrete and set up the 'earth' thing. Then he laid concrete over it. Thus I know earth safety is installed

 

The problem with that is that if it's buried in anything it needs to be exothermically welded, otherwise the connection will potentially corrode away in months. In any case, as others have mentioned, a ground connection should ordinarily be ready for inspection at any time.

[xtrnuno41]

Mmmm, well if i see it right. There is a main 3 phase of 63 A , probably (i can t see from pics) running up to the 2 other 3 phase fuses or just for something else special??.

One is 100 A and the other again 63 A. If the 100 A is serie with the main fuse of 63 A, it makes no sense. The fuse will never respond, as the main will go first then. You loose all power.

Are there more power cables coming in??. And then connected to the 100 A fuse??.

 

The connection bars fixed on the 100 A fuse, easy, but in installations here bars are separated and fitted on the box with isolators and from there you make the wiring connections. Also the bars should be covered with a poly carbonate plastic. These bars are open wide. One simple error can cause a major shortcut and have an enormous explosion. You will be blown away. You already see one bar slightly twisted.

 

Also i see, feed coming in on bottom 100 A and then the feed (from the bars) to the 63 A is going in on top??.

Europe it should be on the bottom going in. Maybe Asia different and power feed going on top???.   

Maybe it is, as i see the neutral also coming in from above and fitted on the ground. Well keeping standard to avoid errors.

I never saw an adjustable differential switch (RCBO), but ok maybe in the east they have. It is set to the lowest position, so ok. But thats with only the main cable running to the 2 other fuses??.

However not very wise to have the differential switch in that. If it detects in the mainpower, all your power from the hospital switches off !!

You can have a earth leakage in the Schneider groups and then all power is gone , just for 1 item. Not wise for hospital.

I also hope they put the neutral to the Schneider groups for having 240 volts. But cant tell.

 

All your Schneider fuses are C20 A, so with C characteristic, more secure are with B characteristics. With C20 it switches off way later then with a B20. Why 20 A? you can do mostly with 16 A, so again more secure.

It all depends on what devices are running on the groups and how the groups spread in hospital.

Maybe there are devices with a high starting current (mostly separate group), so then you need a step higher 20A instead of 16A. But i believe they use C characteristic in Asia often, cheaper??

But otherwise a B16 A with a differential (30 mA) switch , is perfect.

 

Those Schneider fuses arent attached in serie with a differential switch, you could have at least one for 3 groups. Max Amps of the switch is 40 A. Though all of the 3 groups will have no power then anymore. Cheaper but not so handy in hospital.

You should replace the Schneiders for a fuse INCLUDING a differential switch, then every group is more secured and if one group fails, the others stay on. Probably for a hospital important.

 

A differential switch sees the difference form current going in and out. If you have an earth leakage, then the currents differ and it is shut off. Your METAL (hull) device could be under power.

There for all your (metal) devices should be running in a grounded socket and you should have a ground.

 

The question is how deep is the ground rod and is it working properly. Ah OK , just red again about your ground rod and i can tell you now,  very probably not good. Or is there a central ground rod on which you are connected??.

They should measure !! Otherwise its fake !

The rod should be in wet soil deep in the ground (in dry and wet season) !! It can be 30 or 40 meters deep, depending on measurement.

 

Placing a rod working properly, you need a special way to do it and measure !! See on youtube about grounding rods placing !! Let them show you what is the resistance of the rod !!! It should be close to zero !! Special way of measuring !! Otherwise you have fake safety and besides maybe some devices cant work !!   

When they placed the rod dry , wet season and did they measure it??.  What is the material they use for the ground rod??.

For safety, thats why a fuse with differential switch is way better.  

And again i see with the Schneiders some are placed up site down. Not standard again and you can make errors.

 

Also with the Schneiders a loose cable. Is it ground? All metal boxes must be grounded !!! 

 

My opinion sofar, guess engineers in Thailand arent stupid. Maybe other rules. However workman should fix all right, check and double check to drawings. Situation not quite clear.

[tenhoursaway]

Installations in medical locations are special and have to follow

IEC60634-7-710 (respectively the correlating Thai code more or less a copy of aforementioned IEC standard). Depending on the procedures, you may have to have a class 2 room. 

 

The American standard (NFPA99) is NOT APPLICABLE in Thailand. 

 

For more information you may PM me with your Email, so I can send you some information regatding setup for medical locations. Since  posting a link might be considered advertising abd violating forum rules I dont want to post links to the documents here. 

 

One issue I guess from the breakers, they all start with a "C" followed by Ampere rating. Class "C" is NOT for medical locations, actually not even for households. (except air conditioner circuits) You SHALL have class "B", everything else depends on the medical procedures in the clinic. 

 

BR, from Bangkok

[Crossy]

7 hours ago, tenhoursaway said:

Since  posting a link might be considered advertising abd violating forum rules I dont want to post links to the documents here. 

No problem posting a link to technical documents / standards.

 

Which Thai Industrial Standard (TIS) applies for medical locations? They are ridiculously cheap compared with their western counterparts (IEC standards are around USD 100) and will be in Thai for the contractor to understand.

 

[bbabythai]

14 hours ago, xtrnuno41 said:

Mmmm, well if i see it right. There is a main 3 phase of 63 A , probably (i can t see from pics) running up to the 2 other 3 phase fuses or just for something else special??.

One is 100 A and the other again 63 A. If the 100 A is serie with the main fuse of 63 A, it makes no sense. The fuse will never respond, as the main will go first then. You loose all power.

Are there more power cables coming in??. And then connected to the 100 A fuse??.

 

The connection bars fixed on the 100 A fuse, easy, but in installations here bars are separated and fitted on the box with isolators and from there you make the wiring connections. Also the bars should be covered with a poly carbonate plastic. These bars are open wide. One simple error can cause a major shortcut and have an enormous explosion. You will be blown away. You already see one bar slightly twisted.

 

Also i see, feed coming in on bottom 100 A and then the feed (from the bars) to the 63 A is going in on top??.

Europe it should be on the bottom going in. Maybe Asia different and power feed going on top???.   

Maybe it is, as i see the neutral also coming in from above and fitted on the ground. Well keeping standard to avoid errors.

I never saw an adjustable differential switch (RCBO), but ok maybe in the east they have. It is set to the lowest position, so ok. But thats with only the main cable running to the 2 other fuses??.

However not very wise to have the differential switch in that. If it detects in the mainpower, all your power from the hospital switches off !!

You can have a earth leakage in the Schneider groups and then all power is gone , just for 1 item. Not wise for hospital.

I also hope they put the neutral to the Schneider groups for having 240 volts. But cant tell.

 

All your Schneider fuses are C20 A, so with C characteristic, more secure are with B characteristics. With C20 it switches off way later then with a B20. Why 20 A? you can do mostly with 16 A, so again more secure.

It all depends on what devices are running on the groups and how the groups spread in hospital.

Maybe there are devices with a high starting current (mostly separate group), so then you need a step higher 20A instead of 16A. But i believe they use C characteristic in Asia often, cheaper??

But otherwise a B16 A with a differential (30 mA) switch , is perfect.

 

Those Schneider fuses arent attached in serie with a differential switch, you could have at least one for 3 groups. Max Amps of the switch is 40 A. Though all of the 3 groups will have no power then anymore. Cheaper but not so handy in hospital.

You should replace the Schneiders for a fuse INCLUDING a differential switch, then every group is more secured and if one group fails, the others stay on. Probably for a hospital important.

 

A differential switch sees the difference form current going in and out. If you have an earth leakage, then the currents differ and it is shut off. Your METAL (hull) device could be under power.

There for all your (metal) devices should be running in a grounded socket and you should have a ground.

 

The question is how deep is the ground rod and is it working properly. Ah OK , just red again about your ground rod and i can tell you now,  very probably not good. Or is there a central ground rod on which you are connected??.

They should measure !! Otherwise its fake !

The rod should be in wet soil deep in the ground (in dry and wet season) !! It can be 30 or 40 meters deep, depending on measurement.

 

Placing a rod working properly, you need a special way to do it and measure !! See on youtube about grounding rods placing !! Let them show you what is the resistance of the rod !!! It should be close to zero !! Special way of measuring !! Otherwise you have fake safety and besides maybe some devices cant work !!   

When they placed the rod dry , wet season and did they measure it??.  What is the material they use for the ground rod??.

For safety, thats why a fuse with differential switch is way better.  

And again i see with the Schneiders some are placed up site down. Not standard again and you can make errors.

 

Also with the Schneiders a loose cable. Is it ground? All metal boxes must be grounded !!! 

 

My opinion sofar, guess engineers in Thailand arent stupid. Maybe other rules. However workman should fix all right, check and double check to drawings. Situation not quite clear.

''These bars are open wide. One simple error can cause a major shortcut and have an enormous explosion. You will be blown away. You already see one bar slightly twisted.''

 

Thanks for your info. Im worried about reading this. What is the % chance that this can happen?

[bankruatsteve]

15 minutes ago, bbabythai said:

''These bars are open wide. One simple error can cause a major shortcut and have an enormous explosion. You will be blown away. You already see one bar slightly twisted.''

 

Thanks for your info. Im worried about reading this. What is the % chance that this can happen?

Probably not much.  The thing is, they appear to be unnecessary.  It seems the ring terminals on the wires connected to the bars could simply be connected to the breaker without the bars.  A gecko getting inside would certainly increase the chance.

 

Edit: Again, what you should be most concerned with, IMO, are the electrical requirements for the medical equipment you will have in use.  I don't know what they are but I "think" there are some that should NOT be grounded, for example.

[bbabythai]

16 minutes ago, bankruatsteve said:

Probably not much.  The thing is, they appear to be unnecessary.  It seems the ring terminals on the wires connected to the bars could simply be connected to the breaker without the bars.  A gecko getting inside would certainly increase the chance.

thanks for your reply. Which part of which photo are you referring to. are you able to draw an arrow to indicate?

thanks

[bankruatsteve]

1 minute ago, bbabythai said:

thanks for your reply. Which part of which photo are you referring to. are you able to draw an arrow to indicate?

thanks

Sorry, I can't be bothered to do that.  It's the 2nd photo where the breaker has bars coming out to attach wires.

[Led Lolly Yellow Lolly]

I'm sorry I don't have time to answer your PM. I'm happy to offer free advice in passing but the reality is you're not going to be able to fix these problems yourself and the local dimwit spark is probably only going to make things worse and tell you everything is just dandy. If this is a hospital you frankly should have the resources to get a certified electrical engineer on site. 

[sometimewoodworker]

4 hours ago, bbabythai said:

thanks for your reply. Which part of which photo are you referring to. are you able to draw an arrow to indicate?

thanks

You did ask

 

 

if you are in the Northeast (Udon ) I can put you in touch with a real electrician.

[tenhoursaway]

10 hours ago, Crossy said:

Which Thai Industrial Standard (TIS) applies for medical locations? 

TIS 2433-2555

มอก. 2433-2555

 

http://www.fio.co.th/p/tisi_fio/fulltext/TIS2433-2555.pdf

 

The electrical design depends mainly on the procedures in a medical room (see page 6), rooms are classified acc. Group 0, 1, or 2

 

Some more explanations here, (see download link for the brochure) 

https://www.bender-apac.com/solutions/healthcare

 

Please note most of the information in the brochure are for Group 2 rooms. 

[tenhoursaway]

11 hours ago, Crossy said:

 

 

 

3 hours ago, NilSS said:

If this is a hospital you frankly should have the resources to get a certified electrical engineer on site. 

Well said.