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Is there any advantage/disadvantage or restriction to using SY cable for the mains cabling in the fit-out of a new boat? It's not much more expensive than arctic cable but seems to provide additional protection from physical damage and electrical interference.

Also, on this page of the The Fit-Out Pontoon the last para graph states, " The Boat Safety Scheme states that cables should be run as high as possible and ideally 125mm away from potential sources of impact and that conduits must be firmly fixed at 900mm intervals." How should one interpret this? Am I to run all cables around the ceiling and drop down to the sockets and switches? I was hoping to run them in boxed sections behind removable skirtings.

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24 minutes ago, stegra said:

Is there any advantage/disadvantage or restriction to using SY cable for the mains cabling in the fit-out of a new boat? It's not much more expensive than arctic cable but seems to provide additional protection from physical damage and electrical interference.

Looks like good stuff.

However, I know nothing about the prerequisites of mains cabling on boats other than to use Arctic blue, so if the spec exceeds this then although it would seem like a good idea I'll leave others with more knowledge to comment. 

The only disadvantage I can think of is perhaps less flexibility and an increased minimum bending radius compared to 2.5mm2 Arctic, which might make your mains installation more difficult.

Edited by blackrose
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A concern in using this cable is that the steel braid must be correctly bonded to earth, I think it is common practice to use a gland at both ends with a metal box.  In my boat the mains cables are all behind wood panels and fairly well protected from damage, so I wonder if you are solving a problem you don't really have coupled with the disadvantages of terminating this cable.

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What is the flexibility of of SY cable like at low temperatures?

It is the flexibility at low temperstures thst gives "arctic" cable its name.

However this property is only useful for cables that move about or are subjest to vibration at low temperatures. 

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I did wonder about bonding the braiding. I guess I was hoping it wouldn't be necessary and the braid could just be trimmed back and held under a bit of heat-shrink to prevent fraying. As there's an earth conductor present, I thought bonding was perhaps more for protection from electromagnetic interference. My interest was sparked only because it's price is so close to that of arctic. It seems to be a lot more robust for a very small cost.

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3 minutes ago, cuthound said:

What is the flexibility of of SY cable like at low temperatures?

It is the flexibility at low temperstures thst gives "arctic" cable its name.

However this property is only useful for cables that move about or are subjest to vibration at low temperatures. 

Some specs from another vendor here. Might be slightly different if from a another manufacturer.

Conductor         Plain Annealed Copper Class 5 to BS EN 60228

Insulation         PVC Type TI2 to BS EN 50363-3

Sheath         PVC Type TM2 to B EN 50363-4-1

Min Operating Temperature         -15°C

Max Operating Temperature         70°C

Min Bending Radius         6 x ∅

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3 minutes ago, stegra said:

Some specs from another vendor here. Might be slightly different if from a another manufacturer.

Conductor         Plain Annealed Copper Class 5 to BS EN 60228

Insulation         PVC Type TI2 to BS EN 50363-3

Sheath         PVC Type TM2 to B EN 50363-4-1

Min Operating Temperature         -15°C

Max Operating Temperature         70°C

Min Bending Radius         6 x ∅

Spec for arctic cable goes down to -30°C.

Applications:

For use outdoors and where flexibility is required at sub-zero temperatures. The cable remains flexible down to -20°C. Low voltage household appliances under medium mechanical stress.

Conductors:

Plain annealed flexible copper

Insulation:

Arctic grade PVC (Polyvinyl chloride)     

Core Identification:

2 Core:  Blue, Brown

3 Core: Brown, Blue, Green/Yellow

4 Core:  Brown, Grey, Black, Green/Yellow

5 Core: Brown, Blue, Black, Grey, Green/Yellow

7 Core:  Black Numbered + 1 Green/Yellow

Sheath/ Jacket:

Arctic grade PVC (Polyvinyl chloride)

Colour:

Blue, yellow or orange (other colours available on request)

Voltage:

300/500V

Operating temperature:

Maximum 70°C

Minimum -30°C

Minimum bending radius:

3 x diameter

Short circuit temperature:

160°C

Standards:

BS6004

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Hi stegra,

I have just finished renovating my NB and used sy for the AC electrical, i used 3 core sy and bonded the braid at 1 end only as this is  required for the cable protection, if you use a cable gland and strip the outer clear pvc back about 6 inches you can then sleeve this with yellow/green sleeving and terminate either at the socket outlet or in the consumer unit.

All ccts must be supplied via a DOUBLE pole RCD which breaks the L and N at the same time. Most RCD's only break the live poles.

hope this helps

springer

  • Greenie 1
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2 hours ago, Springer said:

 

All ccts must be supplied via a DOUBLE pole RCD which breaks the L and N at the same time. Most RCD's only break the live poles.

hope this helps

springer

I'm not sure the Bss mandates that but in any case most RCDs ARE double pole.

A lot of rcbos only break the live perhaps that's what you are thinking of.

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4 hours ago, stegra said:

Also, on this page of the The Fit-Out Pontoon the last para graph states, " The Boat Safety Scheme states that cables should be run as high as possible and ideally 125mm away from potential sources of impact and that conduits must be firmly fixed at 900mm intervals." How should one interpret this? Am I to run all cables around the ceiling and drop down to the sockets and switches? I was hoping to run them in boxed sections behind removable skirtings.

Anybody able to give a reference to this as I can't find it in the BSS guide?

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44 minutes ago, jonathanA said:

I'm not sure the Bss mandates that but in any case most RCDs ARE double pole.

A lot of rcbos only break the live perhaps that's what you are thinking of.

I think DP mcbs are preferred for hook-up/shoreline in case of reversed polarity in the supply lead. Not sure if they're a requirement.

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41 minutes ago, system 4-50 said:

Anybody able to give a reference to this as I can't find it in the BSS guide?

I'm pretty certain it's 100% certifiable bovine excreta. 

5 hours ago, stegra said:

Also, on this page of the The Fit-Out Pontoon the last para graph states...

Possibly this is from an old guide. Several rules have been relaxed over the years due to their silliness. 

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Looks like great stuff with some additional mechanical strength, but -

  • Why would you need it, if it's not going to share industrial style conduit, or subjected to disturbance when in use.
  • To do it properly you need to provide earth continuity in each joint. If you're using domestic switch sockets, they're a pain enough with just six wires, let alone another two.
  • Some of my bends are quite tight - this stuff won't go as tight. Of course you shouldn't have tight bends....
  • Being an old misery it's a bit of an overkill.  
  • Is it cheaper than Arctic - which is tried and tested?

 

 

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1 hour ago, system 4-50 said:

Anybody able to give a reference to this as I can't find it in the BSS guide?

No but its on the internet so it must be right. Always check with the regulation, not what someone says.

17 minutes ago, OldGoat said:

Looks like great stuff with some additional mechanical strength, but -

  • Why would you need it, if it's not going to share industrial style conduit, or subjected to disturbance when in use.
  • To do it properly you need to provide earth continuity in each joint. If you're using domestic switch sockets, they're a pain enough with just six wires, let alone another two.
  • Some of my bends are quite tight - this stuff won't go as tight. Of course you shouldn't have tight bends....
  • Being an old misery it's a bit of an overkill.  
  • Is it cheaper than Arctic - which is tried and tested?

 

 

And there is no regulation that says it has to be Artic there, but that is what most people seam to use.

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AFAIK there is only one single module RCBO on the market that breaks live and neutral in the event of a fault and that is made by SES and is only available from them. No RCBOs have overcurrent sensing on the neutral which could be a problem if running a supply that is unbonded, genset, inverter etc. You need to be very careful in your selection of device.

Oh and as for SY cable its hatefull stuff only surpassed by SWA. Ordinary white PVC cable or HO7 is fine doesn't need to be Artic

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17 minutes ago, Loddon said:

Oh and as for SY cable its hatefull stuff only surpassed by SWA. Ordinary white PVC cable or HO7 is fine doesn't need to be Artic

Julian,

I vehemently disagree - SY is infinitely worse than SWA cable!  

Chris G

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3 minutes ago, Loddon said:

SWA is more engineering than cable.........

Certainly when you get to interesting stuff - 3 core 240 mm2 motors cables, 630 mm2 transformer tails, etc. are more like pipe fitting than electrical work!

Chris G

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2 hours ago, Batavia said:

Julian,

I vehemently disagree - SY is infinitely worse than SWA cable!  

Chris G

Not used it for years and that was run on tray on a ship we were rewiring for a survey company in 74. It may even had a different name then.

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12 hours ago, stegra said:

Is there any advantage/disadvantage or restriction to using SY cable for the mains cabling in the fit-out of a new boat? It's not much more expensive than arctic cable but seems to provide additional protection from physical damage and electrical interference.

Also, on this page of the The Fit-Out Pontoon the last para graph states, " The Boat Safety Scheme states that cables should be run as high as possible and ideally 125mm away from potential sources of impact and that conduits must be firmly fixed at 900mm intervals." How should one interpret this? Am I to run all cables around the ceiling and drop down to the sockets and switches? I was hoping to run them in boxed sections behind removable skirtings.

Your second para is rubbish. As you have latterly surmised, just use 2.5mm^2 flex. Arctic if you like, but not necessary since it won't be flexing (unless you have a bendy boat). Bear in mind that it is advisable to keep 230v cabling away from 12v cabling unless the former is in trunking or sheathed - Oh but the sheath on a normal type of flex cable counts for that, so fill your boots with 12v adjacent to 230v.

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To clarify... if you used say 2" box trunking for all your cables and ran everything as single wires - 12V+ve, 12V-ve, L, N, E, then that would be against the rules. The mains L, N, E must be sheathed to keep them separate from the 12V stuff. Using flex (Arctic, H07, whatever) provides the required sheath. If you really want to have the extra expense, hassle and inconvenience of armoured then go for it; it's your money, time and effort. 

Obviously, you don't want to run any cables, 12V or mains, anywhere where they're at risk of physical damage, and you do want to ensure they're adequately clipped/tied/trunked/conduited to stop them flopping about. 

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