Ring final circuit test

[Terryjepson]

Hi everyone 

Ive recently tested a ring final circuit on a 3phase 24way D/B st a hotel.

my readings were

Ze= 0.20max reading

L=0.33 N.= 0.33 E= 0.52 R1 +R2 = 0.21

testing at various socket outlets in rooms I’m getting 4.70ohms Zs ??

all earths in place all in Db board earths on ring connected correctly and in earth bar.

Protected by Rcbo type B 32A

can any of you guys possible reason why I’m getting these readings in all sockets on this circuit 14 sockets in total,

i understand earth pins may be worn in socket outlets due to continued use etc but I cannot understand why?

any help/Reason would do   

Cheers 

terry

 

[Sharpend]

Did you check for loose connections? 

You could well have an oldish install where the cores have been twisted together hence the good end to end value but may have been loose in connections of plates? 

 

[Murdoch]

OP - your R1 + R2 figure. Is this calculated or actual readings?

Rcbo's can give higher readings but never seen one that high and as it's off all the sockets I doubt it's the sockets

 

[Sharpend]

Would these new USB sockets give a higher resistance? Not done one so not sure. 

 

[Murdoch]

Would these new USB sockets give a higher resistance? Not done one so not sure. 

Unlikely but they do give very low IR readings

 

[Sidney]

Did you test through the socket-outlets or the terminations on the back of the socket-outlets?