Eicr earth rod over 200ohm

[graham123]

Earth rod measures 247 ohm, with water and gas connected 233ohm. All covered by 30maain rcd.

C3? Improve the rod reading to below 200?

 

[Engineer54]

Earth rod measures 247 ohm, with water and gas connected 233ohm. All covered by 30maain rcd.

C3? Improve the rod reading to below 200?

And if or when the RCD device fails to operate, will 199 ohms be tickety boo??

 

[Guest55]

C3? Improve the rod reading to below 200?

i'd agree with that.

 

[Guest55]

And if or when the RCD device fails to operate, will 199 ohms be tickety boo??

i understand the point youre trying to make , but for a periodic inspection , each defect must be assessed in isolation.
of course a faulty rcd in a TT with a poor earth reading would warrant a C2.

 

[MDJ]

Earth rod measures 247 ohm, with water and gas connected 233ohm. All covered by 30maain rcd.

C3? Improve the rod reading to below 200?

Unstable so a c3 IMO
or preferably as close to 0 as posible

 

[D Skelton]

No code, I'd note it and recommend the customer allow at least a quaterly Ra reading to be taken to further determine it's stability. Another recommendation would be to fit an s-type up front.

Tin hat firmly strapped on!!!

 

[MDJ]

No code, I'd note it and recommend the customer allow at least a quaterly Ra reading to be taken to further determine it's stability. Another recommendation would be to fit an s-type up front.

Tin hat firmly strapped on!!!

I can see your point, and wouldn't consider it a mistake if no code was given, I would suggest a 3 due to the fact it is over the 200 and could be considered unstable and need to be watched or investigated further, a no code is understandable and I think many others will agree with you.

 

[Guest55]

if you dont give a poor rod reading at least C3 then the customer will not feel obliged nor motivated to check on it in the future.
his train of thought will be it cant be that important or a defect code would have been in the report.
to not code it at all suggests that theres no point in having an earth rod at all tbh.

 

[trebor]

The 200 ohms figure is only advisory to allow for freezing or drying out , what were the conditions when you tested ?, the regs only require that the resistance meets the criteria for a given RCD and protective requirement, if you take 30mA for additional protection then thats 1667 or the same device for fault protection its 7667 ohms, and for a 100mA 2300 ohms

 

[MDJ]

The 200 ohms figure is only advisory to allow for freezing or drying out , what were the conditions when you tested ?, the regs only require that the resistance meets the criteria for a given RCD and protective requirement, if you take 30mA for additional protection then thats 1667 or the same device for fault protection its 7667 ohms, and for a 100mA 2300 ohms

That is the reading which will allow the RCD rated at 30ma to trip, we work to the regs regarding RA values, 1667 is not in the regs, your whole post is totally wrong I am afraid.

 

[fredrico]

Table 41.5 page 57.

 

[davesparks]

The calculaion from which the value of 1666.6recurring is in the regs. But it has the advise that a reading above 200ohms may not be stable.

I'd go with a C3 in this case if it was me. My recomendation on how to improve it would depend on whether or not pme is available in the area (walk down the street an look at the poles)

You can't just take the book as gospel, you have to use your skill, knowledge and experience as well.

 

[MDJ]

Table 41.5 page 57.

yes that is the maximum ohm rating to allow a 30ma trip to work in the required disconnection time, we all know that. It is not the maximum allowed RA on a TT system is it, jeez

 

[trebor]

I beg to differ, reg 411.5.3 states that Ra must be equal or under 50V/Idelta n which in the case of a 30mA device is 1667ohms

 

[trebor]

So why is under TT then, how would you calculate the maximum Ra if we are not using RCD`s, i`m not being facitious here, I would really like to see the correct way if im wrong