Eicr ring main readings

[cliffed]

Would you guys be happy with these readings on ring main,Rcbo c type 30ma/32 amp.
r1 1.87...rn 1.91 cpc 3.20....R1 +R2.1.26.
zs 1.46 ohms.

 

[telectrix]

some long ring you have there.
[automerge]1573984432[/automerge]
r!+r2 = 5.07 ohms. this equates to approx. 250m, or there's something wrong.

 

[cliffed]

Yea,would it comply,Max allowed 0.68 ohms,but......

 

[sinewove]

some long ring you have there.

Sounds like roughly 270m of cable there thought max was about 100m of 2.5mm.S

 

[Ian1981]

As long as there is no volt drop concerns for the circuit and the rcbo when tested gives adequate earth fault protection, then it is what it is.

 

[Andy78]

Is it actually that long ? Those would be the highest readings I've ever seen for such a circuit.

 

[Ian1981]

Works out at 258 meters from the R1+R2 result assuming 2.5mm T&E

 

[Baddegg]

What size cable is it?....and why a “c” type?....I have no answer to your question but am genuinely interested ?

 

[cliffed]

2.5 mm lsoh t&e,measurement correct,it’s along one,also did short circuit measurement,according to my cals it does not comply.

 

[cliffed]

Is it actually that long ? Those would be the highest readings I've ever seen for such a circuit.

scary ain’t it.

 

[SJD]

It is quite a long circuit, but from the fact that it is a C32 RCBO, I'm suspecting this is commercial / industrial, rather than domestic? For example, a ring in a large workshop, warehouse, school, etc.

I'd be wondering about the voltage drop, e.g. are all the loads at middle of the ring because the outlets happen to be a long way from the distribution board?

Or has someone used a somewhat too small cable size, e.g. 1.5mm2 T&E or SWA?

 

[cliffed]

It’s in a quite a large office area,it’s defo 2.5mm,difficult to judge where the actual loads are,there are mainly,computers plugged in.Been in service @ least 5 years,all signed of.

 

[Baddegg]

It’s in a quite a large office area,it’s defo 2.5mm,difficult to judge where the actual loads are,there are mainly,computers plugged in.Been in service @ least 5 years,all signed of.

That sounds like most of my customers.....worked fine like that for years ?

 

[telectrix]

It’s in a quite a large office area,it’s defo 2.5mm,difficult to judge where the actual loads are,there are mainly,computers plugged in.Been in service @ least 5 years,all signed of.

if that's the case, why not replace MCB with a B type, even drop to a 20A?

 

[cliffed]

T9

if that's the case, why not replace MCB with a B type, even drop to a 20A?

true that could be done,note on recommendations.
Even rcbo @ 20 amp