Outdoor Flex Cable RR-F or RN-F

[HappyHippyDad]

Just as a little extra....

I still haven't got to the bottom of why H05RN or H07RN is classed as more appropriate for outside use than RR. I am specifically talking about the neoprene inner sheath/jacket of the RN as opposed to the rubber inner sheath/jacket of the RR.

......

However, since writing the above 20 minutes ago I have done a little research on the net. Neoprene is in fact a rubber, a synthetic rubber. In particular neoprene 'resists degradation more than natural rubber' (Neoprene - Wikipedia - https://en.wikipedia.org/wiki/Neoprene). It is relatively inert meaning it does not react with many things, more accurately it is in a 'state of doing little'.

So, in layman's terms I guess we prefer RN as opposed to RR for 'certain' outdoor situations as it lasts longer.

 

[Richard Burns]

I believe water can slowly penetrate the R rubber (EPR) whereas the N rubber, neoprene (polychloropene) the migration is imperceptible.
Therefore where a cable is constantly wet, such as in a pond, the EPR would not be suitable and would fail after a few years, where the cable is say on an outside wall the water will dry off before it can penetrate.

 

[HappyHippyDad]

I believe water can slowly penetrate the R rubber (EPR) whereas the N rubber, neoprene (polychloropene) the migration is imperceptible.
Therefore where a cable is constantly wet, such as in a pond, the EPR would not be suitable and would fail after a few years, where the cable is say on an outside wall the water will dry off before it can penetrate.

That makes sense Richard with regards the use of neoprene, but what about the outer insulation (R) on RN cables? With your above example would this not fail after a few years if constantly wet in a pond?

 

[TaylorD]

That makes sense Richard with regards the use of neoprene, but what about the outer insulation (R) on RN cables? With your above example would this not fail after a few years if constantly wet in a pond?

The RN cable still probably lets the water in under the primary insulation (Rubber) but the neoprene would maybe stop the further migration of water.

Whereas RR cable the inner conductor would probably corrode due to the water migrating through both rubber insulators.

 

[Richard Burns]

That makes sense Richard with regards the use of neoprene, but what about the outer insulation (R) on RN cables? With your above example would this not fail after a few years if constantly wet in a pond?

Insulation is EPR (R), outer sheath is neoprene (N), now thinking about it it is not suitable for continuous immersion just for wet areas, I think.
If you have a RN cable where the junction box gets wet then the water can track up the inner rubber insulation and wreck the cable.
I am sure someone posted a useful post on harmonised cable classification a while ago, giving clarity to the numbering system, I think they were called happyhippydad!

 

[DefyG]

Change the gland to suit the cable you want to use!