Minimum IR

[PEG]

Good evening gents.

Thanks for the helpful advice where given. Warm and dry now. Sorry for the lack of info. It was motorway spec cable. 150Ohms/L is the minimum. Was not thinking straight due to the frost bite setting in but knew it was there abouts.

Think sometimes to often when a question is asked on here the answer is look at the regs. Sometimes you need a little help in a shtt situation.

Cheers

Hi bud,this would have been easier,if we knew the situation and type of cable.

Where has the "1500hms/L" come from? :smiley2: ...or "150 Ohms/L" even?

 

[Lucien Nunes]

The original question asked what the minimum IR value for a 230v cable is as a regs book wasn't to hand, that implies the OP required the minimum value stated in bs 7671...which is 1 megohm!

It's no longer clear exactly what the OP was asking but there's an important difference between the minimum acceptable IR for 70mm² cable and the IR for a circuit using that cable. 1 metre of 70mm² would be considered faulty and rejected if it could only achieve 1MΩ, but wire it between a fuse-switch and a busbar chamber and test it on a damp day and 1MΩ might be realistic. OTOH a 600m run of cable might not be so bad at 1MΩ so when you are looking at larger cables and longer runs you can't just say 1MΩ is the limit and that's that.

Hence the figure in MΩ.km (sometimes misquoted as MΩ/km which is a nonsense) that manufacturers give for each size and type of cable, or they refer to the one in the BS for that cable. If the '150 ohms/l' is supposed to say megohms then it makes sense to me.

 

[LeeH]

I'm confused. What exactly does this '150Ohms/L' mean?

Lorry
Litre
Lepricon?

 

[mat155]

Spanner in the works. 1500 Ohms or 1.5MOhms is the minimum per kilometer / by the Length is the minimum for motorway spec power cable. Typo after one of those days where you are glad to put behind you. Thanks all the same.