Quality and safety difference in RCBO, RCD, MCB and CU

[djtheoz]

Hi there folks, 

working on a new consumer unit in the house and noticed a sigificant price difference in e.g. Schneider or ABB components with for example NANO components. 
For example a Schneider 32A RCBO (859B) compared to a NANO 32A RCBO (377B). 

Or a 14 slot CU from Schneider S9HCL114 (1.365B) compared to a NANO PCU12 (624B). Ok, 2 slots less, but half the price?

Is this difference because of added import taxes on the Schneider components or is the quality in NANO just lower and significantly less safe?
E.g.. why would one NOT pick the cheaper brands? Any thoughts?

 

[KannikaP]

Check where the Schneider are made, probably in China. But if you are worried, get the expensive ones, only about Bht1200 difference.

[carlyai]

I've got Schneider consumer units. That's what the electrician recommended at the time. He spent a lot of time wiring up factories, so maybe they use these products in factories.

They don't have a DIN rail, so you have to buy their circuit breakers. Their lightning protection MOV s are too expensive (I feel) over B1000 each where as a DIN mount is about B250. 

I did have one CU fail. The incoming 3 phase line connects to screws that should be tightened with a tension wrench. Maybe they were overtightened on connection because they started to fizzzz then arc. A few years later that I noticed, so I replaced the unit. They are well made and strong, but you don't have the flexibility you would with DIN connections I think.

[djtheoz]

58 minutes ago, carlyai said:

 

They don't have a DIN rail, so you have to buy their circuit breakers.

Both the Schneider and NANO examples are plug-on type breakers for use in their own CU series. Haven't compared the DIN mounted series yet... 
Both brands seem to comply with the IEC standards. 
Just wondering what the more-than-twice the price for the same functionality is caused by.
 

[sometimewoodworker]

1 hour ago, carlyai said:

I did have one CU fail. The incoming 3 phase line connects to screws that should be tightened with a tension wrench. Maybe they were overtightened on connection because they started to fizzzz then arc. A few years later that I noticed, so I replaced the unit.

The requirement for a tension wrench is for those who don’t have the feel for tight enough, or who have safety police breathing down their necks.
 

Over tightening will not do what you described, that is under tightening, over tightening could strip the threads if you try hard enough.

[bodga]

11 minutes ago, sometimewoodworker said:

The requirement for a tension wrench

compulsory in the UK now

[sometimewoodworker]

2 minutes ago, bodga said:

compulsory in the UK now

No it isn’t, recommend yes, required no.

 

if you think it is please quote or reference the regulation.

[djtheoz]

Reading several other threads on this forum about this RCBO's , I even see Chinese stuff from Ali Express coming by as OK to use... ?
For my old fashioned brains this seems a big no-no but pardon my ignorance...
I understand people can be brand-favored and will be happy spending twice the amount no matter how good the other brand is..  

 

But IS there a significant safety/quality difference that explains the price difference? 
 

 

[bankruatsteve]

Square D products in the states have been reliable installations for decades.  Brand name trustworthy.  The Chinese brands come and go and not much history - so that's the price difference.  Should be able to make your own decision by comparing for the quality.

[carlyai]

11 hours ago, sometimewoodworker said:

The requirement for a tension wrench is for those who don’t have the feel for tight enough, or who have safety police breathing down their necks.
 

Over tightening will not do what you described, that is under tightening, over tightening could strip the threads if you try hard enough.

Yes overtightning would strip the thread, precisely what I meant. Thread stripped causing a HR joint. So depending on the lever you use with the key, it's difficult to gauge the tightness. Not saying the electrician caused the fault, but he liked to give all connections a heafty tweak at the end when he re-checked.

[Led Lolly Yellow Lolly]

FWIW I have quite a high failure rate with Schneider RCBOs. I'm not sure why but I think it's probably down to lightning transients. I've not lost any ABB or Siemens DIN RCDs or RCBOs, so I switched away from Schneider and plugin systems altogether on new installs.

 

 

 

 

[carlyai]

15 hours ago, NilSS said:

FWIW I have quite a high failure rate with Schneider RCBOs. I'm not sure why but I think it's probably down to lightning transients. I've not lost any ABB or Siemens DIN RCDs or RCBOs, so I switched away from Schneider and plugin systems altogether on new installs.

 

 

 

 

Yes I think that's the way to go. Also you have to be careful with the plugins as it's easy to break off the back parts. Not just me, but the electrician broke one as well.

[djtheoz]

Thanks for tips so far.

DIN solution seems more interesting to add an over/under voltage & surge protection and a VU-meter.
A setup with all rcbo's from ABB or Siemens would be great, but is way over budget.

But, if it’s worth it, safety has to come first. Just more noodle soups need to be sold ????
Unfortunately I'm not able to check out things in Thailand myself due to covid, though the misses needs some direction and get material.

All replies very much appreciated , thank you for your time!

Consider these two setups -  which would you choose for your house, and why (not) ?

Setup 1 – Only RCBO with NANO Plus (Thai brand & make) ~ Total 4.905 B
1 x Nano Consumer unit 16U metal (type CUO14 ) = 472 B.
1 x Nano MCB / Mains 2P-63A (type PMD42C63) = 83 B. 

2 x Nano RCBO 32A (type PLE31C32) = 870 B
8 x Nano RCBO 16A (type PLE31C16) = 3.480 B

 

Anyone has experience with this brand? I only used it for junction boxes before..

Mostly when it seems to good to be true.. it is..

Setup 2 – Split circuit with ABB (German brand, China make) ~Total 8.840 B.
1 x ABB Consumer unit 16U (type SCP16) = 2.300 B.

1 x ABB MCB/ Mains 2P-63A (type S202M-63C) = 750 B.

2 x ABB RCD 63A (type FH202AC-63) = 4.600 B

2 x ABB MCB 32A (type SH201-C32) = 238 B.

8 x ABB MCB 16A (type SH201-C16) = 952 B.

 

The 32A groups are wired with 2x4/2,5 sqmm, others with 2x2,5/1,5 sqmm.

We’re on a single phase 15(45) kWh meter connection.

 

 

[djtheoz]

Just realising the boxes are too small to add the extras...will get a bigger  box ☺️

[mipa123]

@djtheoz I'm exactly in the same position. NANO, CHiNT or Schneider/ABB - unfortunately your conversation ended here. which one you chose in the end and what was your reason + experience so far?

[OneManShow]

I used Schneider for my house (safety 1st, ฿1k or ฿2k not important. How ever I believe all brands work the same way, more or less.

[OneMoreFarang]

Maybe it was mentioned already.

If you want to make sure you get protection from RCCBs and RCBOs, make sure you buy Type A. They are more expensive and maybe difficult to get in Thailand. But they work in modern households with modern devices.

If you are interested, google it.

https://www.electrical-installation.org/enwiki/Types_of_RCDs

 

 

 

 

 

[sometimewoodworker]

On 1/11/2025 at 12:34 PM, OneMoreFarang said:

Maybe it was mentioned already.

If you want to make sure you get protection from RCCBs and RCBOs, make sure you buy Type A. They are more expensive and maybe difficult to get in Thailand. But they work in modern households with modern devices.

If you are interested, google it.

https://www.electrical-installation.org/enwiki/Types_of_RCDs

 

 

 

 

 

The class of RCD is actually rather more complicated than your recommendation. Certainly the class C units that are ubiquitous are usually the wrong ones. I have some circuits where class C is correct however the majority should be class B as should the majority of domestic installs. 
There are few electricians working on domestic installs and even fewer will do, or be asked to do, the circuit tests that will tell you which breaker type is suitable and which will only trip when the fault is dramatically larger than they should be triggered.

 

The classes of circuits where a C type breaker is correct are ones with large inrush currents like my woodworking power tools with ¾ HP ~ 2 HP and up motors, also pumps will typically need a class C 

 

The correct class of breaker requires proper circuit testing and few have the equipment required, training in its use, or are paid for the time that is needed to use it. An earth resistance metre is expensive and because an earth resistance test is never required for a domestic instal check nobody has them.

 

TLDR type C are used because few installing understand why they should not and they don’t nuisance trip on circuits with a pump.

 

I am sure that my installation would not pass a proper safety check however it is good enough and though I do know an actual electrician I don’t think it is worth getting him to do an actual check. In the U.K. a safety check is a legal requirement for many so you must pay the ฿25,000 an up inspection fee.

[OneMoreFarang]

1 hour ago, sometimewoodworker said:

The class of RCD is actually rather more complicated than your recommendation. Certainly the class C units that are ubiquitous are usually the wrong ones. I have some circuits where class C is correct however the majority should be class B as should the majority of domestic installs. 
There are few electricians working on domestic installs and even fewer will do, or be asked to do, the circuit tests that will tell you which breaker type is suitable and which will only trip when the fault is dramatically larger than they should be triggered.

 

The classes of circuits where a C type breaker is correct are ones with large inrush currents like my woodworking power tools with ¾ HP ~ 2 HP and up motors, also pumps will typically need a class C 

 

The correct class of breaker requires proper circuit testing and few have the equipment required, training in its use, or are paid for the time that is needed to use it. An earth resistance metre is expensive and because an earth resistance test is never required for a domestic instal check nobody has them.

 

TLDR type C are used because few installing understand why they should not and they don’t nuisance trip on circuits with a pump.

 

I am sure that my installation would not pass a proper safety check however it is good enough and though I do know an actual electrician I don’t think it is worth getting him to do an actual check. In the U.K. a safety check is a legal requirement for many so you must pay the ฿25,000 an up inspection fee.

 

I am not sure if we talk about the same "thing". My post was about RCBOs and RCCBs with Type A or Type AC.

AC is what was/is mostly in use. And it was for a long time good enough for "old" devices with transformers, etc.

A is for devices with switching power supplies, which is now very common.

As far as I know is some, maybe many countries, now they must use Type A.

This short video explains what it's about.

 

 

 

[sometimewoodworker]

4 hours ago, OneMoreFarang said:

 

I am not sure if we talk about the same "thing". My post was about RCBOs and RCCBs with Type A or Type AC.

AC is what was/is mostly in use. And it was for a long time good enough for "old" devices with transformers, etc.

A is for devices with switching power supplies, which is now very common.

As far as I know is some, maybe many countries, now they must use Type A.

This short video explains what it's about.

 

 

 

RCBO’s come in types A AC F and  B

AC are in general in other countries are not permitted as the do not deal with D/C

So for general use type A or type F are best

 

FWIW I have 2 x AC’s and 1 x A 

 

MCB’s come in B, C and D tripping curves  this is domestic and ignores those above D

 

Tripping characteristics:

• Type B devices are designed to trip at fault currents of 3-5 times rated current (In). For example a 10A device will trip at 30-50A.
• Type C devices are designed to trip at 5-10 times In (50-100A for a 10A device).
• Type D devices are designed to trip at 10-20 times In (100-200A for a 10A device).

So looking at my post above which was not very clear I was talking about MCB’s not RCBO’s