Does anyone understand what the markings on heat resistant flex mean.
I had to connect up an induction hob this morning, the instructions
specified: HO5 RR-F 3 core 4.0mm, so I went out to try and get some.

The first wholesaler didn't have any 3 core 4.0mm (not unusual in my experience.

The second wholesaler had what they described as heat resistant rubber flex in 3 core 4.0mm, a make called LINEAX at an eye watering cost of around £6.00 per metre.
On that cable the marking is: HO7 RN-F.

What does it all mean?

Off the top of my head: H is for Harmonized (i.e.common type across Europe - there's a different letter for national types) - 05 / 07 etc is the voltage rating 05=500V, 07=700V etc. I think the others are insulation types & conductor stranding. I've see a chart somewhere, I'll try and dig it out.
- Andy.

H05RR-F is a light duty cable rated at -25 to +60 C 300/500V
H07RH-F is heavy duty -20 to + 60 (or 85 for static applications)
450/750v
Both really used for trailing leads etc.
You could I suspect use 3093Y flex ( 85 degree rated) as you probably don't actually need mechanical protection.
Regards
Marc

Try the first table here: http://www.internationalconfig...nts/2004Catalog/m.pdf

HO5 RR-F = Harmonised, 300/500V, Rubber insulation, Rubber sheath, fine wire stranding (flex).

- Andy.

HO7 RN-F has a nitrile rubber outer sheath which is heat and oil resistant and much tougher. What was the hob circuit loading, was it really 5-6kW? Seems to me it may be over specified.

-------------------------
David
CEng etc, don't ask, its a result not a question!

Yes, the rating plate on the hob showed something like 6.2kW.

Many thanks for all replies, very helpful.
Mike