RCD disconnection times on 2018 forms

[S P]

Evening all, happy Friday!

On the new forms there is only one column for RCD disconnection times.
I understood you would just record the highest of the 5x readings but on looking around to confirm I found this article on Professional-Electrician:

"The model forms in Appendix 6 have been changed so there is now only one box to record the highest disconnection time for an RCD test. Stroma recognises that this new provision may cause confusion in the industry and advises that where RCDs are provided for Additional Protection, inspectors should carry out X1 and X5 tests and record the highest disconnection time measured on the new form."

18th Edition: Changes to Inspection & Testing - https://professional-electrician.com/18th-edition/18th-edition-changes-inspection-testing/

I read this as the highest overall of the 4 readings, which will likely be 1x.

Thoughts?

 

[Stspark]

The highest reading to meet the requirements of fault protection or additional protection. 1x or 5x will depend on what you're testing for.

 

[TJ Anderson]

RCD'S are tested in relation to thier function e.g. 30mA RCDs providing additional protection tested at 5x (0 &180 deg) and highest value recorded.
RCD'S rated 100mA or higher used to provide fault protection or fire protection, tested at 1x (0&180deg) and highest value recorded.

 

[Zdb]

I now record ×5 for additional protection and ×1 for most others.

 

[S P]

Thanks, that makes sense.
So do as Zdb mainly

 

[Deleted member 9648]

I prefer to record both the highest 1x and 5x values regardless of the new requirements. There is enough space in the box to write (for example) 38.2/18.8.
In the description of work I state that readings are recorded as 1x/5x (maximum measured value).

 

[Deleted member 26818]

I believe, we are only supposed to record the 1 x I delta n.
The 5 x I delta n test can be performed to prove the device provides additional protection, but there’s no requirement to record the result.

 

[Dave OCD]

I believe Spinlondon is spot on.

 

[S P]

I prefer to record both the highest 1x and 5x values regardless of the new requirements. There is enough space in the box to write (for example) 38.2/18.8.
In the description of work I state that readings are recorded as 1x/5x (maximum measured value).

That made me laugh!
Not if you write on the ones from the book..

 

[S P]

I second guessed the earlier advice as I've read much good advice from yourselves, Spin and OCD..
So on further research I found this, which I believe backs up the previous thoughts:

"Where an RCD is provided for Additional Protection it must have a tripping current (IΔn) of 30mA or less and trip at 5 x IΔn in 40ms or less. Therefore, for a 30mA RCD a test current of 150mA needs to be applied to ensure the 40ms disconnection time is achieved. It is unnecessary and inappropriate to test RCDs with nominal tripping currents above 30mA, such as 100mA RCDs, at 5 x IΔn as they do not provide Additional Protection.

Where an RCD is installed for Fault Protection or Fire Protection they should be tested at the nominal tripping current, 1 x IΔn, to ensure that the disconnection time is achieved for the type and rating of the circuit and the earthing system employed. For example, where provided for fault protection on a TT earthing system for final circuits up to 32A the RCD should trip at less than 0.2s (200ms)."

http://files.stroma.com/certification/stroma-technical-guide-rcds.pdf

 

[Deleted member 9648]

I believe, we are only supposed to record the 1 x I delta n.
The 5 x I delta n test can be performed to prove the device provides additional protection, but there’s no requirement to record the result.

Just to clarify I wasn't suggesting recording both times is a requirement, merely that I still prefer to do so.

 

[gazdkw82]

On the "new" minor works forms from guardian who do all our testing, there is only an option to record x1. I've questioned it.