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V

volers

Hi guys ths is my first time on here and relatively new to electrics. I was asked to find the times of disconnection needed for 5x and 1x. I was wondeering if anyone could give me a push in the right direction by pointing out where i could find such useful info inthe BS 7671 or onsite guide. THank you. Volers
 
As per the On-site Guide

- A disconnecting time of not more than 0.4 sec is required for final circuits with a rating not exceeding 32A.
- A disconnecting time of not more than 5.0 sec is required for final circuits exceeding 32A, and distribution circuits.

You have to enter the maximum value of x1 & x5 on your report sheet.

Hope this helps!
 
i am looking through bs7671 in the inspection and testing chapter, however I am unable to find the relevant info on disconnection times at different rated currents. Also it keeps referring in the book back to chap. 41. sorry to be a pain and asking such simpleton questions but i want to make it my single mission to get a better understanding of inspection and testing this week!!!
 
thanks Goody ii didnt read your post before replying... thats great help. i think my main problem is trying to locate where to extract info from in the holy 7671 book.
 
As per the On-site Guide

- A disconnecting time of not more than 0.4 sec is required for final circuits with a rating not exceeding 32A.
- A disconnecting time of not more than 5.0 sec is required for final circuits exceeding 32A, and distribution circuits.

You have to enter the maximum value of x1 & x5 on your report sheet.

Hope this helps!




According to the table yellow van man has pointed out... the max trip time for 30 mA at 1x is 300ms.
 
i am looking through bs7671 in the inspection and testing chapter, however I am unable to find the relevant info on disconnection times at different rated currents. Also it keeps referring in the book back to chap. 41. sorry to be a pain and asking such simpleton questions but i want to make it my single mission to get a better understanding of inspection and testing this week!!!

Hi
When you test a 30 mA RCD you should start at : positiv side - O * (degree)
- 1/2 x I ^n (^ is delta) - (15 mA ) no trip within 2000mS
- 1 x I^n (30 mS) --trip within 200 mS
- 5 x I^n (150 mS) -- trip within 40 mS
repeat hte same at negativ side -180 *
you rec. the highest value ( longest time)
 
seems to be some confusion over trip times of MCBs and RCDs. RCD times are 300msec.@ x1. 40msec.@ x5. ( TT systems it's 200msec.@ x1. )
 
All disconnection times are listing in the On-Site Guide page 92. If you are taking your 2330 302/303 make sure you label your On-Site with post-its so you can access the information quicker.
 
seems to be some confusion over trip times of MCBs and RCDs. RCD times are 300msec.@ x1. 40msec.@ x5. ( TT systems it's 200msec.@ x1. )

Lol, there's more confusion:

Don't forget Note 2 of table 41.1 whereby the TT disconnection time of 0.2s is for fault currents 'significantly higher than the rated residual operating current of the RCD'
In other words, the 0.2s disconnection time does not apply to 1 X IΔn tests.
 
Lol, there's more confusion:

Don't forget Note 2 of table 41.1 whereby the TT disconnection time of 0.2s is for fault currents 'significantly higher than the rated residual operating current of the RCD'
In other words, the 0.2s disconnection time does not apply to 1 X IΔn tests.

note 2 says typically 2xIdelta n. how are we supposed to test that when all testers test at 1x and 5x?
 
note 2 says typically 2xIdelta n. how are we supposed to test that when all testers test at 1x and 5x?

The official line is that if the disconnection times for the BS are met on 1X and 5X then it can be taken that the 2X will be met.

One of my suggestions at the Guidance Note 3 amendment meeting was for a better explanation of this process-I've even heard some that didn't understand this advocate the use of a BS4293 device to meet the 200ms time!
 

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