Zs reading across RCD

[beaver74]

Hi all

with a heathy ZE ..22 on a TN-s system i had a R1+R2 of .40 oh my suprise to find that the Zs was 1.01at the furthest socketrechecked my ZE.22??
rechecked ZE from out going terminals of RCD .60 has any one else found this

ps i realise that this reading is fine as RCD protected just wondering

 

[jam2020]

yeah i had this today as you know, head scratcher!!

 

[malcolmsanford]

Hi all

with a heathy ZE ..22 on a TN-s system i had a R1+R2 of .40 oh my suprise to find that the Zs was 1.01at the furthest socketrechecked my ZE.22??
rechecked ZE from out going terminals of RCD .60 has any one else found this

ps i realise that this reading is fine as RCD protected just wondering

No trip or D lock setting on the meter by any chance

 

[R&M]

Ya I've seen this too, several times. But sometimes this internal resistance of RCCB is really high. Mostly it's about 0.20ohm to 0.30ohm but in some occasions it's 0.50~0.60ohm. RCBOs have less in my experience. I mentioned this issue in IET forum couple of months ago and outcome was it's normal, nothing to be worry about. But is this this really ok or not, you should judge yourself.

 

[beaver74]

Ya . But is this this really ok or not, you should judge yourself.

as for the reading no problem in the higher Zs as it is protected by the RCD .but i was more concerned about the fact you can have such a differance acroos what is in effect a swithed set of contacts

 

[Amp David]

Always get a slightly higher reading when using the no trip function as opposed to the high current loop test.