Pat testing a 50m extension lead

[BillyTheSparks]

Hi,

I have a pat test job coming up soon, it's for a landscaping business and I know that they have 10m/25m/30m and 50m extension leads which they use for there cement mixers etc.

Looking at the leads they're only 1.25mm^ 3core. So where do I stand with the maximum length shoud be 12m??

Thanks in advance

 

[armbands0]

Hi, if the extension lead is over the prescribed length then it must be used with an RCD of 30mA or less residual operating current. You should remind the owner of this requirement.

Voltage drop is also a problem to consider, all this on pages 78/79 of the code of practice.

Figures for resistance of stranded copper @ 1.25mm is 37mV/A/M at 50M with max current rating of 13A. Vd is 24V

You can but tell them.

 

[BillyTheSparks]

Thanks for the advice, Ive just had a look at the CoP and found the info you have pointed out.
I'll Let the owner of the premises know the advice.

Cheers

 

[grantr37]

would say that the core size is too small for the load that the mixers will place, and as mentioned above, all outside equipment should be used with an RCD as well as being of a suitable IP(Ingression protection) rating for use where rain might get into it, would they be better off using a generator as opposed to plugging into the mains? maybe worth thinking about but wouldnt want to offend them so would just go with the RCD mention, again with voltage drop I think that general opinion is that the extension leads should not be more than 25 metres.
You may want to offer to change standard plug tops for a commando style blue 220v industrial trailing plug and socket set up, this is safer and is water resistant as far as rain goes, you can get them cheaply at screwfix trade counters or delivered from Screwfix, wholesalers tend to take a liberty with these types of plugs as they see them as "industrial use"

 

[BillyTheSparks]

Thank you grantr37, I get on well with the chap who owns the business and will put your suggestions across. He's a good bloke and switched on about things, and will probably listen to the advice given.

thanks again.