Hi can someone tell me whether I need to record the trip times on x1 or x5 on this combined device,as I'm getting trip times of 44/45 ms x1 and sometimes a lot lower ie 29 ms.This device is the sole means of isolation.
Cheers
Cheers
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Discuss RCD/ combined afdd breakers in the UK Electrical Forum area at ElectriciansForums.net
If the 30ma device is for additional protection bottom line is you need both the x5 tests to be less than 40ms, record the highest of the two x5 readings. (EDIT if you only have space for one reading)
The two x0.5 tests (no trip) and two x1 tests ( < 300ms ) still need checking of course.
The two x0.5 tests (no trip) and two x1 tests ( < 300ms ) still need checking of course.
You're recording the characeristics of the RCD element of the device, nothing else, so you're recording both. And if your times are <300mS on 1x and <40mS on 5x then you're all good. One thing that's changing is that the newer type A / B / F RCD's tend to have longer times than the AC types we're all used to, but perfectly acceptable.
Hi Tim
Cheers for that ,but the device is a combined RCD/afd and is designed for fault protection,and not additional protection,so guess it's the highest x1 value of both sides of the wave .
The pedant in me needs to point out that the device is the device (in this case a combined RCBO & AFD) - it has no say in how it gets deployed and doesn’t know what level of protection it’s been put into circuit for. Ergo, you test it the same as any other device - RCD times and compliance (on the circuit) for ADS times.
What test current are you applying for the 5x test as some of the newer breakers are designed to operate at a higher trip current of 250ma and not the usual 150ma
I'm actually a bit confused what the actual question is and if it's been answered! ;-)
When you say it's for fault protection are you referring to the AFDD part of it, or meaning it's installed to provide ADS for an installation, e.g. a main switch or up front device on a TT system?
The time/current criteria is in Appendix 3 of 18th, page 363
Also see reg 643.8, note underneath.
However if it is for fault protection and providing ADS for an installation then chapter 41 applies.
If we can help more then feel free to tell us a bit more about how/where this thing is installed, and what you are unsure of. ;-)
When you say it's for fault protection are you referring to the AFDD part of it, or meaning it's installed to provide ADS for an installation, e.g. a main switch or up front device on a TT system?
The time/current criteria is in Appendix 3 of 18th, page 363
Also see reg 643.8, note underneath.
However if it is for fault protection and providing ADS for an installation then chapter 41 applies.
If we can help more then feel free to tell us a bit more about how/where this thing is installed, and what you are unsure of. ;-)
Hi Tim
I'm working on a youth hostel ,and this is a brand new install ,this relates to one of two three phase boards ,of which almost every single phase breaker is a combined RCD/AFD device ,just would like to know the maximum Ms for the x1 test at 30mA.
Regards
Wow, sounds like someone was flush with cash! Do you have a photo?!
Anyway, posts 2 and 3 are correct, irrespective of the fact they are combined devices, maximum 300ms at 30ma (x1), maximum 40ms at 150ma (x5).
The x5 time still needs to be complied with and if you only have one box to write a result (like the latest NAPIT model form) you'd write down the biggest x5 value.
(The only extra complexity is if the earthing is TT then the x1 would need to be under 200ms)
Hope that helps.
Anyway, posts 2 and 3 are correct, irrespective of the fact they are combined devices, maximum 300ms at 30ma (x1), maximum 40ms at 150ma (x5).
The x5 time still needs to be complied with and if you only have one box to write a result (like the latest NAPIT model form) you'd write down the biggest x5 value.
(The only extra complexity is if the earthing is TT then the x1 would need to be under 200ms)
Hope that helps.
Hi Tim
Thanks so much for that ,and it's a TNS SYSTEM ,and the device is for fault protection and not additional protection so it should be the highest result on the x1 setting at 30 mA
Many thanks
Can send pic tomorrow if you want ,and yes guess the boards and breakers are expensive ,and was designed by Siemens.
Regards
Ray
I am struggling to understand this.
You have a cu, (std switch on incoming) and each outgoing circuit has a combined rcd/afdd - is this correct?
If so where is the overcurrent protection for each circuit (fault and where needed overload)?
You have a cu, (std switch on incoming) and each outgoing circuit has a combined rcd/afdd - is this correct?
If so where is the overcurrent protection for each circuit (fault and where needed overload)?
As far as I'm aware these are MCB/RCD double pole devices with AFD protection ,these are bespoke boards made especially for the job I'm on . Hope this helps ,but thanks guys and girls I have all the info now .
Regards
Ray
Honestly I'm a bit baffled too, I'm aware of a Siemens MCB + AFDD product, and ordinary RCBO's, and some clever lego-like add on units to add AFD protection (see below), but I've never heard of an AFDD and RCD combo without overload protection too.
Prepared to be proved wrong, and intrigued to see a photo.
I'm concerned that I have given you the wrong answer to what might turn out to be the wrong question!
![[ElectriciansForums.net] RCD/ combined afdd breakers](https://www.electriciansforums.net/attachments/1624559404447-png.87051/ "[ElectriciansForums.net] RCD/ combined afdd breakers")
Prepared to be proved wrong, and intrigued to see a photo.
I'm concerned that I have given you the wrong answer to what might turn out to be the wrong question!
Ahh so rcbo/afdd devices NOT rcd/afdd.
They are quite different from rcd/afdd.
I think you need to check exactly what you have as the question you asked doesn't appear to reflect the equipment you have.
If its for additional protection only you only need to do the 5X test at either 150mA or 250 mA if the 150 don’t comply , though personally i still do all 6 test as its what I’m used to, and it seems a better way to me.
Sorry i thought you said its a TN-S Supply , it would only be fault protection if on a TT.
L
loz2754
Or if every circuit has been so poorly designed that ADS cannot be achieved by coordination between the device and the EFLI, leading to the use of RCDs for fault protection.
I have a feeling we're not in possession of the full and accurate facts ?
Hi these are double pole rcbos with combined Afd ,all I would like is the maximum mS parameters for x1 and X5 for the rcbo ,this is the sole protection ,each individual circuit is covered by one of these .
Regards
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