Help please

[sivoodoo]

Just been looking at a condition report from a property a friend is buying.

Its a TT system, Ze measured at 200 Ohms earth rod.

Ring final circuit 2.5mm, 30mA RCD, the measured Zs is 9.8 (max allowed is 1.44)

There is a 100ma main switch with operating time of 327ms.

The report says Satisfactory, is this the case???

Thanks

 

[telectrix]

max. Zs for a circuit protected by a 30mA RCD is 1667 where the RCD is used for fault protection.

 

[Paul.M]

What is the R1+R2 measurements on the RFC? Lets break it down stage by stage.

 

[sivoodoo]

R1+R2 = 0.32
r1=0.36 rn=0.39 r2=0.87

 

[Paul.M]

R1+R2 = 0.32
r1=0.36 rn=0.39 r2=0.87

But yet the Zs = 9.8 Ohms??????

Ze can not be 200 Ohms, test it and find out the true readings.

Tel as already said it, RCD as an up front fault protection. I also think that the Ze on that test sheet has been made up. Bet the true Ze reading is 9.7 Ohms??????

 

[sivoodoo]

that's what im thinking, in fact all other 8 circuits show a measured Zs of 9.8.
Age of the installation estimated at 35 years.
IR readings are +20 on all circuits.
I've not tested it. This is someone else's report.

 

[telectrix]

Zs values brought down by gas/water bonding? if as you seem to say, all circuits are recorded as 9.8 ohms, then it's made up.

 

[Paul.M]

Do a "true" Ze test and take it from there. That 200 Ohms on the sheet is rubbish imho. Made up in the van whilst counting the money.

This is your friend so just go and do a few tests. Rip that EICR to bits.

 

[Spearmint]

Do a "true" Ze test and take it from there. That 200 Ohms on the sheet is rubbish imho. Made up in the van whilst counting the money.

This is your friend so just go and do a few tests. Rip that EICR to bits.

Paul is right, that stupidly high Ra figure is just ripped from the OSG. Test it yourself.

 

[sivoodoo]

yes ill try get access again and test. The place is ancient the cutout is antiquated, one socket per room etc. My friend is trying to get some money knocked off the price of the house. But this report says its satisfactory, what should i do if my test results are wildly different?

 

[Spearmint]

yes ill try get access again and test. The place is ancient the cutout is antiquated, one socket per room etc. My friend is trying to get some money knocked off the price of the house. But this report says its satisfactory, what should i do if my test results are wildly different?

Explain the results and offer recommendations needed (if any), let him make the choice.

 

[Paul.M]

But this report says its satisfactory, what should i do if my test results are wildly different?

Test it to your ability with the qualifications you have to back you up and shove it in the face of anyone that questions your results. That works for me.

Look, at the end of the day testing is physics. We test the actual metal conductor and the insulation which it is protected by. Your testig it, you tell who ever the results and just tell them "This is physics" you cant change the laws of the universe ffs. Stick it to them if need be.

 

[sivoodoo]

Thanks ill keep you posted

 

[trev]

yes ill try get access again and test. The place is ancient the cutout is antiquated, one socket per room etc. My friend is trying to get some money knocked off the price of the house. But this report says its satisfactory, what should i do if my test results are wildly different?

What I'd do is invite the person who carried out this EICR round for a chat. Ask him/her to explain the results and the contents of the report, all the while saying nothing about what you're doing for a living.
When he's finished and looking all smug and self satisfied then, and only then, pull out your test results and ask him to explain the anomilies.
I'm an intransigent old bar steward though.

 

[Paul.M]

^^^^ done that twice, very satisfying^^^^