Multicore fixed installation options

[Oggi]

Hi Guys,

I need a 5 core control cable with a run of about 15m from an extractor to a control box in my loft, multicore flex (3185Y would be ideal) is easily available & cheap but is generally not used for fixed installations as far as I'm aware, so can anyone suggest a substitute? Multiple cables would be a route I'd rather avoid but at a push would two or more cables be a suitable (if not very neat) substitute?
I also noticed that TLC don't recommend PVC flex (3185Y specifically) for use in an environment where oil and/or grease may be present? Why would that be the case when equvalent T&E is sheathed in (what I assume) is the same stuff and has no warning. Being an extractor environment there may be some build up of oil/grease over time...

Have a top weekend....

 

[ericmark]

Oil and grease can remove the plasticizer from the plastic and working with cars you often find the installation has become more brittle. With a fixed cable this is not too much of a problem but where flexing it is so the warning is more to do with use of cable we expect flex to flex.

There are multi-core cables but often you need to buy a role and to recommend a cable which is not locally available would not be helpful.

However three phase neutral and earth adds up to 5 so there should be loads of cables you can use but of course any wire coloured green and yellow must be used for earth.

Do however watch the voltage there are loads of extra low voltage cables in 7 cores.

 

[ColJack]

what's wrong with flex for fixed wiring?

if you're that bothered then something like multicore FP cable might be an option.

some oils and greases will damage the PVC insulation, and others will damage rubber insulation, it depends on the type of oils and greases expected.. ( that's the reason you may need some hoses changed on your car / van if you start using bio-diesel.. which is in effect strained cooking oil.. it eats away at the hoses.. )

 

[LoveRocket]

( that's the reason you may need some hoses changed on your car / van if you start using bio-diesel..which is in effect strained cooking oil.. it eats away at the hoses.. )

I'm afraid that's a long way off, Col. BioDiesel is NOT 'strained cooking oil' although it can be made from used cooking oil. (and certain old engines can run on cooking oil) BioDiesel is produced by chemical process called transesterification - the veg oil is reacted with methanol to produce a Fatty Acid Methyl Ester - a completely different substance from the original oil (which is a tri-glyceride). I believe it is the methyl content that can cause certain rubbers in the fuel system to fail.

Sorry to go completely off topic, but that is a common misconception that causes 1) People to be put of perfectly good BioDiesel because they think it's just 'strained cooking oil' and 2) people get ripped off by some merchant selling old cooking oil as 'BioDiesel' and end up with a big repair bill in their 2009 CDI.

 

[Oggi]

Thanks guys, that's a help, I suppose as primarily it'll be a fixed installation there won't be a lot of flexing going on.
As it's a control circuit the currents involved are tiny so I think going the 3-phase route would be a little of overkill, I'm not familiar with the smallest CSA's available but I imagine they would be larger than I need.
I'm aware of the alarm type control cables that are not mains rated, I think the 3185Y route is probably the best bet.
I just wanted to be sure there wasn't something obvious I'd missed.

 

[holmslaw]

..

 

[ColJack]

( that's the reason you may need some hoses changed on your car / van if you start using bio-diesel..which is in effect strained cooking oil.. it eats away at the hoses.. )

I'm afraid that's a long way off, Col. BioDiesel is NOT 'strained cooking oil' although it can be made from used cooking oil. (and certain old engines can run on cooking oil) BioDiesel is produced by chemical process called transesterification - the veg oil is reacted with methanol to produce a Fatty Acid Methyl Ester - a completely different substance from the original oil (which is a tri-glyceride). I believe it is the methyl content that can cause certain rubbers in the fuel system to fail.

Sorry to go completely off topic, but that is a common misconception that causes 1) People to be put of perfectly good BioDiesel because they think it's just 'strained cooking oil' and 2) people get ripped off by some merchant selling old cooking oil as 'BioDiesel' and end up with a big repair bill in their 2009 CDI.

the first diesel engine was run on peanut oil and was intended all along to run on agriculturally produced oils..
it's only that the petrolium industry had a waste product that could be used as a cheap and readily available substitute that we all became dependant on fuel oil..

from what I researched you filter the bits out then "wash" it with ethanol ( or methanol ) and lye.. ..
isn't that the same thing they do to make soap? to seperate out the glycerine ( the bit we're trying to remove? ).. doesn't that make biodiesel a byproduct of making soap?

so methanol is anti-freeze, and lye is drain cleaner?

 

[LoveRocket]

Right then Col, you're on the right track, but you're falling for the BioDiesel confusion.

Yes, Rudolph Diesel's first engines ran on peanut oil, and yes, the petroleum industry then realised that what was then a waste product from the distillation of petrol could be used to run them - hey presto heavy oil became Diesel Fuel.

ANY diesel engine can be made to run on vegetable oil, but you can't just pour cooking oil in to the tank of modern ultra-high injection pressure direct injection engines.

Some older, Indirect injection Diesel engines CAN run on cooking oil without conversion - if they have suitable injection pumps. Peaguot-Citroen XUD engines with a Bosch rotary IP and Mercedes OM61x and 60x engines are the best. To use recycled cooking oil, you need to seriously filter the oil and remove any suspended water. If you have a suitable engine then this can then be used. (A common engine 'conversion' is to use a twin-tank system, where the engine is started on petroDiesel then switched to oil once up to temperature (and then purged with Diesel at then end of the journey)

But BioDiesel is COMPLETELY different, and proper made BioD can be used in pretty much ANY diesel engine.

To make biodiesel, the oil is reacted with methanol using potassium or sodium hydroxide as a catalyst. As I said, veg oil is a tri-glyceride; the molecule look like an "E" with long tails, the E being the glycerol and the long tails being the fatty acid ester chains. The catalyst breaks the bond between the glycerine and fatty acid chains, and then the methanol combines with the fatty acids. (Hence Fatty Acid Methyl Ester) After reaction you are then left with 'BioDiesel' and glyc. You must then remove the glyc, any remaining methanol and the soaps produced. Soap is formed when Free Fatty Acids react with the lye, and also as a product of reaction with glycerine.

This is the same (roughly speaking) process as used to make soap, but with organic soap making, the BioD is the waste product!

There's loads of good info on the net, look it up mate! But to summarise: BIODIESEL IS NOT COOKING OIL!!!

 

[RF Lighting]

Surely YY cable is what the OP is after, but I don't see any problem with using flex for a fixed installation.

 

[plugwash]

Aren't YY and flex pretty much the same other than the colour codes?