EHU 2.5mm flex

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Sep 23, 2023
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One example I once came across was a three phase motor running off 2.5 mm twin and earth,I told the owner who wasn't aware of a problem,Next day I called back having isolating previously and carried out several other issues with it
 
Dec 27, 2022
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I would guess that well over 70% of caravan cables don't meet the HO7RN-F standard.
General PVC cables don't , Arctic cable doesn't
I know neither of my cables do, really must get around to changing them.
HO7RN-F is a specific type of EPR/PCP based cable which anything with a PVC sheath isn't.

I won't mention cables built without ferrules as that a whole other can of worms 😉
 

JTQ

May 7, 2005
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I won't mention cables built without ferrules as that a whole other can of worms 😉
Oh please do, I want to understand what used in this context these "ferrules" are and the attributes they bring. I suspect I can't be alone in wanting to learn.

Re the quoted HO7RN-F spec, AI search is coming up with "Voltage Rating: 450/750V for flexible use, with higher ratings for fixed installations. "
So on the face of it not really required for our 240 VAC EHU application?
 
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Dec 27, 2022
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HO7RN-F is the cable specified under BS7671 to be used for caravan hook up cables.

As for ferrules they are crimped over the copper strands of a cable to prevent the screws in the connector from breaking/damaging the cable strands.
Many people just don't bother with them.
 
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JTQ

May 7, 2005
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Thanks.
Yes, now found that spec, "or equivalent" is called up.

Bedtime reading for those of us still in the willing to learn phase.

One German EHU cable I recall did feature those brass crips on the core ends.
 
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May 30, 2024
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When I was in France this summer and came across a 'reverse polarity' hookup I was very pleased to find that my EHU cable (new in 2024) needed no tools to remove the plug, nor even swap the conductors because the wires (equipped with ferrules) terminated into those quick wire sprung connectors.
 
Dec 27, 2022
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When I was in France this summer and came across a 'reverse polarity' hookup I was very pleased to find that my EHU cable (new in 2024) needed no tools to remove the plug, nor even swap the conductors because the wires (equipped with ferrules) terminated into those quick wire sprung connectors.
Being really picky. When assembling IDC connectors one should not use ferrules since the IDC connection grips bare wires better😱

I used to prefer building IDC cables as I could build twice as many in a given period and since I was on piece work it paid double.
 
Oct 19, 2023
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HO7RN-F is the cable specified under BS7671 to be used for caravan hook up cables.
I had to do some digging when I read this. I've only ever come across HO7 in black (I was surprised to find that it was available in other colours) and I know for sure that my hook up cable isn't HO7 as it's isn't rubber sheathed (I thought that it was PVC....)

Are you sure that HO7 is specified? I don't have access to BS7671 at the moment, but the link JTQ provided and another reference I found both state:

'The cable should be to the harmonized code H05RN-F (BS EN 50525-2-21) or equivalent'

EN 50525‑2‑21 applies to flexible cables, insulated with crosslinked elastomeric compound, and sheathed with either crosslinked elastomeric compound or thermoplastic polyurethane (TPU).

I'm guessing (hoping) that my cable is TPU not PVC, I'll check tomorrow.
 
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JTQ

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Interesting, and a point I missed picking up, now there are both HO5 & HO7 in the discussion.

AI comes up with this comment to my question, "HO5RN-F vs HO7RN-F";

" H07RN-F is a heavy-duty industrial cable, while H05RN-F is designed for lighter-duty portable equipment and appliances".
Plus, with HO5 being rated at a lower more appropriate to our application 300/500 Volts usage, whereas HO7 is quoted at 450 to 750volts.
But accepting increased reserves is in itself not necessarily a negative, though it can be, eg, re weight, cost and here along with possible lower flexibility impact on its practical usability.

What is the saying, "Every day is a 'school day' "
Thanks.

Our black, more rubber like and ferruled German EHU cable supplied by Hymer certainly comes across with its greater diameter as more "industrial". However, simply because its so heavy has in our case seen no caravanning use, though its ideal for using mains power tools down in the garden.
That cable incidentally is quite supple and flexible despite its diameter, this along with being more rubber like hinting its elastomers are very different materials to those used in our orange EHU cable.
 
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Dec 27, 2022
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Having worked with both, H05 is nowhere near as resilient as H07 , the outer sheath tears more easily if snagged. As a company we took the decision to only use H07 on our systems.

BS7671 is not law, however in the event of an accident then if you haven't followed it's recommendations then you will have the difficult job of proving it wasn't your fault.
 

JTQ

May 7, 2005
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But what specifically has BS7671 to say on our caravanning EHU cables?

Is it directing and accepting the use of the lighter duty HO5 or only the heavier duty higher voltage rated HO7?

Agreed come litigation not following the regulations can seriously impact one's defence, but here to be constructive we really need to know what that BS7671actually states for our EHU cables.
 
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I don't have the latest copy of bs7671 but here are the words from it.

The connecting flexible cable
The means of connecting the caravan to the pitch socket-outlet should be provided with the caravan. This must have a plug at one end complying with BS EN 60309-2 and a flexible
cable with a continuous length of 25 m (±2 m). The connecting flexible cable must be in one
length, without signs of damage, not contain joints or other means to increase its length, and have a connector, if needed, that is compatible with the appropriate appliance inlet. The cable should be to the harmonized code H05RN-F (BS EN 50525-2-21) or equivalent, include a protective conductor, have cores coloured as required by Table 51 of BS 7671:2008+A3:2015 and have a cross-sectional area as shown in Table 7.1 of BS 7671:2008+A3:2015.

The reference to H07 is new in the latest edition, previously it only mentioned cable sizes and connectors.
 
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Nov 11, 2009
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I assume the comment about not including joints to increase cable length doesn’t rule out one of these? I carried one plus an extra 10 m of cable just in case.






The CMHC statement on cable specification and advice is below. Oops!!!!


 
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I assume the comment about not including joints to increase cable length doesn’t rule out one of these? I carried one plus an extra 10 m of cable just in case.




I just use IP67 connectors rather than a box or bag. I've seen to many wet connections that have been wrapped and not dried out.

AFAIK the reason for 25 meters as a maximum length is due to the impedance of the earth wire becoming to high to guarantee 100% operation of RCDs etc.
 
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I don't have the latest copy of bs7671 but here are the words from it.

The connecting flexible cable
The means of connecting the caravan to the pitch socket-outlet should be provided with the caravan. This must have a plug at one end complying with BS EN 60309-2 and a flexible
cable with a continuous length of 25 m (±2 m). The connecting flexible cable must be in one
length, without signs of damage, not contain joints or other means to increase its length, and have a connector, if needed, that is compatible with the appropriate appliance inlet. The cable should be to the harmonized code H05RN-F (BS EN 50525-2-21) or equivalent, include a protective conductor, have cores coloured as required by Table 51 of BS 7671:2008+A3:2015 and have a cross-sectional area as shown in Table 7.1 of BS 7671:2008+A3:2015.

The reference to H07 is new in the latest edition, previously it only mentioned cable sizes and connectors.
The current CMHC advice picks up on HO7 but I wonder how many find it as it’s right down in supplementary information, and just looking at ads for EHU 25m cables very few give details of the specification, although it may be on the cable but just nor stated in the advert.


 

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