Discuss Cable reels pat testing in the Electrical Testing & PAT Testing Forum area at ElectriciansForums.net
Unwound the 25m reel was failing at 0.56 ohms. Before I started doing the maths to check !You can get extension reels in all sorts of length I see Screwfix selling a 45m one, from a reputable supplier. We have a rule of thumb that where the earth bond exceeds 0.18 ohm (I believe this equates to the suggested lengths in the CoP) that it is recommended it is only used with 30ma rcd protection, of course this does not take into consideration any volt drop issues.
Seaward Apollo 500 + I thought there was a built in calculator but couldn’t work it out on site. Have to read the manual again?What tester are you using? Some have settings for different length reels or a setting to put your own pass/fail value in if it's an odd length reel.
Are you talking about the RCD on the DB ??? They’re certainly not using a plug in RCD.You can't take them out of service for not having RCDs. The socket feeding them will more often than not have RCD protection.
Are you talking about the RCD on the DB ??? They’re certainly not using a plug in RCD.
Always wondered what the red button was for. ?
I'm pretty sure that's what is on my 50m cable reel, certainly not an RCD, I think its old enough that RCD's where not available back then.To be fair a lot of the red buttons are just overload reset buttons.
13A fuses have Zs limit of 2.3 ohms (Table 41.2) so assuming your supply Zs is around 1 ohm at the socket then if your cable R1+R2 is 1.3 ohm or less no problem?
Not as such.They do give specific limits on length in the ISITEE code of practice though.
Not as such.
They recommend max lengths of 12/15m for 1.25/1.5mm CSA in section 10.10, and also that longer leads should have RCD protection but that might be part of the installation.
However, 15m of 1.5mm is only 0.36 ohm R1+R2 (from OSG Table I1) so well short of any limit on OCPD disconnection.
Where is 'table 15.4' located?But surely table 15.4 must be followed. And extension are tested as non fixed equipment, ie. separately to the installation.
It is a little shorter, works out at 13.5m of 1.5mm flex, not allowing for plug/socket resistance (which ought to be very small).We have a rule of thumb that where the earth bond exceeds 0.18 ohm (I believe this equates to the suggested lengths in the CoP) that it is recommended it is only used with 30ma rcd protection
Actually if using the resistance from OSG it is about 15mIt is a little shorter, works out at 13.5m of 1.5mm flex, not allowing for plug/socket resistance (which ought to be very
It is an issue for pass/fail equipment intended for relatively unskilled use, and even for the devices that give you an earth bond reading it is not always made clear how to decide if it is a fail (for short cable, as high R must be dodgy connection) or a pass (for extension lead of a given length).I think the text in the 4th edition could be clearer, mainly for when 'PAT testers' rather than electricians are doing the testing. We obviously have more knowledge than people who would often be doing the testing.
Be prepared for disappointment!Be interesting to see how it is shown in the 5th edition when I get hold of it.
Must admit I expected them to be the same but explains the difference.Interesting, as that is about 10% difference for what ought to be the same area of copper!
If you limit the length of extension cables, all you're going to get is multiple extension leads daisy chained together.
The object of the exercise should be safety. A 100m extension lead is far safer than four 25m ones, which will have three plug and socket joints lying around in random places, getting wet, getting crushed or forming trip hazards.
But is it up to PAT/ISITEE testing to determine if a commercial product, like a 100m lead, is safe or not by design?Very true. But someone who is PAT/ISITEE testing should be using the code of practice.
Thought Murdoch was back then???I'm not blaming the guy doing the testing, I'm blaming the ivory tower enclosed muppets that draw up ill thought out legislation.
If a worker needs power 100m away from the nearest power outlet, then he's going to do whatever it takes to get the power there. Those drawing up the legislation should be aware of this and legislate accordingly.
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