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Name the breaker. (Dorman Smith BS3871 Type D).

Sparkingchip

I an trying to determine the maximum Zs for the spare 16 amp MCB with a 5 second disconnect time. 

The maximum Zs of the SWA distribution circuit will be less than 1.4 ohms using a third core as the CPC not including the armour, so it will be lower.

Edit- taking Ze as 0.8 ohms TNS.

professional-electrician.com/.../

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      @Burn

    JP and Burn are correct it is a Dorman Smith consumer unit. I tried reading the side of the MCB with my new Boddington 1000v insulated inspection mirror and taking photos with my phone,  but stopped short of removing a MCB, it's not a consumer unit to get over involved with and as Ze is 0.20 ohms and Zs is 0.59 ohms there isn't a problem. 

    Could it be a Dorman Smith BS3871 D16 MCB, was there such a thing made, as it looks like a Type D to me?

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  • 0

      @Burn

    JP and Burn are correct it is a Dorman Smith consumer unit. I tried reading the side of the MCB with my new Boddington 1000v insulated inspection mirror and taking photos with my phone,  but stopped short of removing a MCB, it's not a consumer unit to get over involved with and as Ze is 0.20 ohms and Zs is 0.59 ohms there isn't a problem. 

    Could it be a Dorman Smith BS3871 D16 MCB, was there such a thing made, as it looks like a Type D to me?

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