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**Sir Liamalot** · 26-11-2020, 11:51

I'm having issue with nuisance tripping.
2U RCBO works fine 20A 30mA, trip time 28ms
1U RCBO is nuisance tripping 32A, 30mA trip, time 25ms and 8ms with a 180° offset.

I'd rather use the 1U for reasons but it's too sensitive. If I get another will it be the same?

Hager AD920J (2U)
Hager ADA332G (1U)

**2011** · 26-11-2020, 12:19

Are these feeding nonlinear loads?
I do not see why the width of the device and nuisance tripping would be related.
In terms of reliability I would consider Schnieder Electric RCBO’s to have the edge on Hager. Schnieder make 1 mod RCBO’s.

**Sir Liamalot** · 26-11-2020, 12:31

Synchronising inverters tripping with load transfer feeding the house (test load). So yeah fridge motors and leds.
It does it with purely resistive loads too though. It's something to do with the phase shift.

**Sir Liamalot** · 26-11-2020, 12:43

Quote:

Originally Posted by 2011

Schnieder make 1 mod RCBO’s.

Acti-9 won't fit unless I put them upside-down...

**Sir Liamalot** · 26-11-2020, 13:07

I just ordered a Schneider EZ9D16832
Rebranded GET so I'm not 100% on yer brand confidence.

I'll let you know if it fairs any better. Cheers.

Pasteur. · 26-11-2020, 13:57

They should be fairly random the trip times shouldn't they?

Anything over 1/2 I∆N

Are.any of single mod units actual double pole switching?

**2011** · 26-11-2020, 15:07

Quote:

Originally Posted by Sir Liamalot

Synchronising inverters tripping with load transfer feeding the house (test load).

The high frequency PWM switching of inverters can cause nuisance tripping.
This can still be an issue even if the inverters are supplying a resistive load.

**Sir Liamalot** · 26-11-2020, 16:45

I swapped the RCBO. Had no problem with the last one. I only use low frequency inverters because they're waaaay better and the HF requirement of B-type RCDs are a waste of money I could just spend on transformer surge capability instead.

Pretty consistent trip times on a digital RCD tester.
Occasionally didn't nuisance trip when the master and slave gensets were harmonising or swapping roles but did most of the time.

There's no fault on the load side.

**Sir Liamalot** · 26-11-2020, 16:56

1U RCBOs only interrupt the Live. Single phase TN-S application.

And yes both sets are TN-S but not at the same time.
A double pole would be better in hindsight but I sacrificed the space to metering and a 16A sub.

Pasteur. · 26-11-2020, 17:03

Quote:

Originally Posted by Sir Liamalot

1U RCBOs only interrupt the Live. Single phase TN-S application.

And yes both sets are TN-S but not at the same time.
A double pole would be better in hindsight but I sacrificed the space to metering and a 16A sub.

Don't think double pole is strictly required for TN

**Sir Liamalot** · 26-11-2020, 18:50

It's not. Would be for floating applications which is a possibility (like right now ironically). I can always put a module inline on a fly lead for this. It's not something I'd elect to do without good reason though. TN-S is my prefered method.

**2011** · 26-11-2020, 18:58

Quote:

Originally Posted by Pasteur.

Don't think double pole is strictly required for TN

As far as I recall it is a requirement in ROI. I will look later if I get a chance.

Anyway 1 mod wide RCBO's are available with 2 pole switching.

**Sir Liamalot** · 26-11-2020, 19:03

Do building regs apply when there's no building or/nor utility involved?

If you do find a reference I'd appreciate the feedback. I like the space-saving so would bias 1Us for this.

I'll have a look for double pole breaking too. Obviously better.

Pasteur. · 26-11-2020, 19:44

Quote:

Originally Posted by 2011

As far as I recall it is a requirement in ROI. I will look later if I get a chance.

Anyway 1 mod wide RCBO's are available with 2 pole switching.

I haven't checked either but I think they use the phrase

"Neutral reliably at earth potential" for everything TN

Which means only have to switch the phase/ line

Pasteur. · 26-11-2020, 19:46

Quote:

Originally Posted by 2011

Anyway 1 mod wide RCBO's are available with 2 pole switching.

That's good to know thanks

26-11-2020, 11:51	#1
Sir Liamalot Combobulator Join Date: Mar 2010 Posts: 5,009 Adverts \| Friends Mod: Motorhomes, Campervans & Caravans, ZTest	Are Single Module RCBO faster reacting than Double Module? I'm having issue with nuisance tripping. 2U RCBO works fine 20A 30mA, trip time 28ms 1U RCBO is nuisance tripping 32A, 30mA trip, time 25ms and 8ms with a 180° offset. I'd rather use the 1U for reasons but it's too sensitive. If I get another will it be the same? Hager AD920J (2U) Hager ADA332G (1U)

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26-11-2020, 12:19	#2
2011 Moderator Join Date: Apr 2009 Posts: 10,524 Adverts \| Friends Mod: Home Automation & Internet of Things (IOT), HST, Electrical, Wicklow, ZTest	Are these feeding nonlinear loads? I do not see why the width of the device and nuisance tripping would be related. In terms of reliability I would consider Schnieder Electric RCBO’s to have the edge on Hager. Schnieder make 1 mod RCBO’s.

26-11-2020, 12:31	#3
Sir Liamalot Combobulator Join Date: Mar 2010 Posts: 5,009 Adverts \| Friends Mod: Motorhomes, Campervans & Caravans, ZTest	Synchronising inverters tripping with load transfer feeding the house (test load). So yeah fridge motors and leds. It does it with purely resistive loads too though. It's something to do with the phase shift.

26-11-2020, 13:07	#5
Sir Liamalot Combobulator Join Date: Mar 2010 Posts: 5,009 Adverts \| Friends Mod: Motorhomes, Campervans & Caravans, ZTest	I just ordered a Schneider EZ9D16832 Rebranded GET so I'm not 100% on yer brand confidence. I'll let you know if it fairs any better. Cheers.

26-11-2020, 13:57	#6
Pasteur. Join Date: Nov 2020 Posts: 248	They should be fairly random the trip times shouldn't they? Anything over 1/2 I∆N Are.any of single mod units actual double pole switching?

26-11-2020, 16:45	#8
Sir Liamalot Combobulator Join Date: Mar 2010 Posts: 5,009 Adverts \| Friends Mod: Motorhomes, Campervans & Caravans, ZTest	I swapped the RCBO. Had no problem with the last one. I only use low frequency inverters because they're waaaay better and the HF requirement of B-type RCDs are a waste of money I could just spend on transformer surge capability instead. Pretty consistent trip times on a digital RCD tester. Occasionally didn't nuisance trip when the master and slave gensets were harmonising or swapping roles but did most of the time. There's no fault on the load side.

26-11-2020, 16:56	#9
Sir Liamalot Combobulator Join Date: Mar 2010 Posts: 5,009 Adverts \| Friends Mod: Motorhomes, Campervans & Caravans, ZTest	1U RCBOs only interrupt the Live. Single phase TN-S application. And yes both sets are TN-S but not at the same time. A double pole would be better in hindsight but I sacrificed the space to metering and a 16A sub.

26-11-2020, 18:50	#11
Sir Liamalot Combobulator Join Date: Mar 2010 Posts: 5,009 Adverts \| Friends Mod: Motorhomes, Campervans & Caravans, ZTest	It's not. Would be for floating applications which is a possibility (like right now ironically). I can always put a module inline on a fly lead for this. It's not something I'd elect to do without good reason though. TN-S is my prefered method.

26-11-2020, 19:03	#13
Sir Liamalot Combobulator Join Date: Mar 2010 Posts: 5,009 Adverts \| Friends Mod: Motorhomes, Campervans & Caravans, ZTest	Do building regs apply when there's no building or/nor utility involved? If you do find a reference I'd appreciate the feedback. I like the space-saving so would bias 1Us for this. I'll have a look for double pole breaking too. Obviously better.