Zdb ok but no R1 + R2

[Delboy10]

Hi All i know its late friday, but try and help me out with this one if you can.
Just got in now from work on the way home a landlord called me to ask if i could test a communal DB he has at an HMO.
I decided to have a look on the way home, long story short each flat was feed from this DB including the communal circuits(lights,sockets).
so i checked Zdb to each flat which was ok but when i did R1+R2 test on the supply cable to each flat i got nothing,tried to each flat and 4 out of the 5 came back with a zero reading.
Distribution board was contactum,each flat was feed from a 40 amp b type mcb (No RCD on DB).

Any thoughts as its got me wondering, the Zdb to each flat was ok but R1+R2 no reading at all.

 

[Deleted member 9648]

What was the distribution cable to each flat?.....Are you sure you were testing each distribution circuit with the L-E linked out at the other end?....

 

[SimpleSimon]

An r1+r2 is a dead test, you were doing a dead test right?

Sent from my GT-I9100 using Tapatalk

 

[SPARTYKUS]

When you say "zero reading" do you mean that or do you mean no reading/ open circuit? Zero would be a great reading.

 

[spamwize2]

Hi you must be taking readings from somewhere other than phase and earth? How are you checking each flat?..
1. have you got Zs and Ze to compare?

 

[Delboy10]

each flat had a 10mm t+e feed from the distribution board,and yes i am sure i was testing each distribution circuit with the L+E linked out,

 

[Delboy10]

yes mate it was tested dead

 

[Delboy10]

sorry i meant no reading i.e open circuit as you say

 

[spamwize2]

so have you got Ze?

 

[fuzzydunlop]

........

 

[Delboy10]

i am taking my readings from phase and earth to each flat from the main distribution board is dead with the earth and phase linked out.
i thought it might be my tester (fluke 1653)but i checked my own house when i got back tested fine,double checked the cal quickly witb my cal card.all ok.i have zs and ze for the installation,i will post those tomorrow as i am out at the inlaws at the moment so i will post it in the morning.

 

[spamwize2]

As we all know Zdb is a reading where all earth connected:
to get Ze we do what?

 

[Delboy10]

remove the main earth from the distribution board so to prevent parallel paths

 

[spamwize2]

ok try that u will be sorted. Zdb will be within tolerance easy

 

[Amp David]

Even if hes testing with main earth and bonding connected, then removing them ain't going to make an R1 R2 figure appear.

Must be testing wrong, if submains are T and E then can't see how R2 can be lost