Tri-rated vs singles

[rick]

Is it OK to use tri-rated cable in conduit rather than singles (6491X)? Obviously of correct rating. If so, why would anyone buy singles as the tri-rated is cheaper and seems nicer to use (I have not used it before until very recently, hence the question).

Cheers

 

[freddo]

Yes, but you need to use bootlace ferrules or similar at all the terminations. Local factory here is wired all over with it.

 

[cliffed]

Usually tri rated used in boiler house install,due to high temperatures.
its more flexible,& very easy to handle @ bigger diameters,like 185mm tails.
Always used in TPN connecting onto bus bars etc.

 

[pc1966]

Also a fan of tri-rated, more so for the bigger sizes (e.g. 25mm) where it is massively easier to work with. But as already pointed out by freddo you should use ferrules so it is cleanly clamped (so fine strands all kept together).

Recently I got one of the self-adjusting crimp tool that do 0.5-10mm sizes and that is a great advantage over trying to guess the correct slot for the usual style of tool. Mine is a cheapo eBay special for around £15 but if you work a lot then I would suggest the better made ones from Knipex (part 97 53 04) or RS (part 122-1790):

RS PRO Hand Ratcheting Crimp Tool for Wire End Sleeves, 0.14 → 10mm² Wire | RS

uk.rs-online.com

For the bigger sizes like 10-25mm I was not very happy with the profile of the cheaper tool I had from CEF or somewhere like that so recently got the fairly expensive RS crimp tool (part 683-1614) instead:

RS PRO Hand Ratcheting Crimp Tool for Wire End Sleeves, 10 → 25mm² Wire | RS

uk.rs-online.com

Having said that, once you have the cable in a proper terminal and tightened up to the right torque they all end up the same sort of shape anyway!

DNOs generally won't accept it though, they only test/approve the various accessories for the usual 7-strand stuff (some are even iffy about the 19-strand one that Doncaster Cables do which is also a whole lot easier to work with).

 

[davesparks]

Is it OK to use tri-rated cable in conduit rather than singles (6491X)? Obviously of correct rating. If so, why would anyone buy singles as the tri-rated is cheaper and seems nicer to use (I have not used it before until very recently, hence the question).

Cheers

Where are you getting tri-rated cheaper than singles? It's normally more expensive, especially when you add the cost of ferrules for the terminations.

I've just checked prices online for 100m of 1.5mm
Tri rated £15.64
6491X £13.00
6491b £14.50

Other possible issues with smaller sizes of tri rate are that it's not so easy to get multiple conductors into a terminal when they've got ferrules on, and multi conductor ferrules will be worse than twisted conductors when taking things apart for fault finding.

I normally use standard singles up to 4mm, tri rated for anything 16mm or larger, and whatever I've got in stock/suits the job for the sizes in between.

 

[Simon47]

I've just checked prices online for 100m of 1.5mm

But you can get 1mm in tri-rated.

Other possible issues with smaller sizes of tri rate are that it's not so easy to get multiple conductors into a terminal when they've got ferrules on

You can use bare ferrules (without the plastic funnel bit) which gets around that problem - but to say it's a PITA getting the strands into them would be an understatement ?

 

[freddo]

I use bare ferrules a lot, used a load today! But I'm not sure I'd use 1.0mm singles in an installation. Isn't there a regulation saying 1.5mm minimum?

 

[James]

one thing to remember, the cable ratings are for conductor temp of up to 90 degrees.
you may need to go up a cable size if you are running close to max capacity.
assuming you are using devices and terminals that are rated for 70 degrees.

http://www.batt.co.uk/upload/files/triratedpanelwiring6001000v105degctobs6231ulcsacurrentratingstablebec100_1219731558.pdf

 

[pc1966]

I use bare ferrules a lot, used a load today! But I'm not sure I'd use 1.0mm singles in an installation. Isn't there a regulation saying 1.5mm minimum?

I rarely use them, more for lights/appliances where you are terminating in to small screw terminals.

In the past we mostly used the miniature DIN rail terminal blocks and commoned 2-3 as needed so we would not need more than one cable per screw.
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one thing to remember, the cable ratings are for conductor temp of up to 90 degrees.
you may need to go up a cable size if you are running close to max capacity.
assuming you are using devices and terminals that are rated for 70 degrees.

That is a good point, same as for the 6243B sort of T&E that can run hot, think it through!

 

[davesparks]

But you can get 1mm in tri-rated.


You can use bare ferrules (without the plastic funnel bit) which gets around that problem - but to say it's a PITA getting the strands into them would be an understatement ?

Yes you can get 1mm tri rated, but how often is that going to be of any use in a conduit/trunking install?
Unless there is only one circuit in the conduit for its entire run then the grouping factors will almost certainly negate the use of 1mm in this type of installation.

It is common to use 2.5mm for lighting circuits and 4mm minimum for power circuits in larger trunking/conduit installs due to grouping.

 

[pc1966]

Yes you can get 1mm tri rated, but how often is that going to be of any use in a conduit/trunking install?

I have used a lot of the thinner tri-rated from 0.5mm to 1.5mm but in control panel style of situation and they generally don't have the same thermal issues.

As the CSA decreases the insulation becomes the dominant factor on overall diameter so its not like you can fit that many more in to a pipe, etc. Unless you had a real need to get the thinnest/cheapest, it probably makes sense to stock reels of the slightly larger sizes (1.5mm upwards).

 

[rick]

Thanks for all the replies. Good point about the ferrules, but I have loads in stock for terminating flex.

Davesparks - TLC have Tri-rated cheaper than singles:

1.5mm² Black 6491X - £17.60 / 100m
1.5mm² Tri Rated Cable - Black - BS6231 - £15.23 / 100m

TBH I don't use singles much either, but based on this I think tri-rated is the way to go for the infrequent times I do (usually a single run to an outside light).

Cheers guys.

 

[Pete999]

Thanks for all the replies. Good point about the ferrules, but I have loads in stock for terminating flex.

Davesparks - TLC have Tri-rated cheaper than singles:

1.5mm² Black 6491X - £17.60 / 100m
1.5mm² Tri Rated Cable - Black - BS6231 - £15.23 / 100m

TBH I don't use singles much either, but based on this I think tri-rated is the way to go for the infrequent times I do (usually a single run to an outside light).

Cheers guys.

In conduit or trunking?

 

[bigspark17]

Can you get trirated Conductors inside an swa?

 

[davesparks]

Davesparks - TLC have Tri-rated cheaper than singles:

1.5mm² Black 6491X - £17.60 / 100m
1.5mm² Tri Rated Cable - Black - BS6231 - £15.23 / 100m

TBH I don't use singles much either, but based on this I think tri-rated is the way to go for the infrequent times I do (usually a single run to an outside light).

Cheers guys.

That 6491x is overpriced, that's not a reason to use tri rated, it's a reason to go elsewhere and get a better price.
[automerge]1590046516[/automerge]

Can you get trirated Conductors inside an swa?

No, tri-rated cable is single insulated flexible conductors.
Thats like asking if you can get unarmoured SWA.