Aluminium wiring

[Piratepete]

Hi Guys and Dolls.
I've just been asked to replace the consumer unit in a house with pvc/aluminium cored cables. - First time for me.
Current unit is the standard rewirable Wylex. The cables look in good condition though failed an overall L+N/E insulation test - until I investigate further, could be nasty or something simple such as a nightlight or extension cable with suppression.

What do I need to look out for? Also how are the cables rated? I guess theyre not 2.5/1.5 and 1.0/1.0 ?

Is there any problem clamping these wires up in modern mcb's?

Please give me your experience.
Thanks
Pete

 

[telectrix]

as ali cables become very brittle over time, it usually means a rewire. your poor IR readings could be bad cable.

 

[IQ Electrical]

Hi Guys and Dolls.
I've just been asked to replace the consumer unit in a house with pvc/aluminium cored cables. - First time for me.
Current unit is the standard rewirable Wylex. The cables look in good condition though failed an overall L+N/E insulation test - until I investigate further, could be nasty or something simple such as a nightlight or extension cable with suppression.

What do I need to look out for? Also how are the cables rated? I guess theyre not 2.5/1.5 and 1.0/1.0 ?

Is there any problem clamping these wires up in modern mcb's?

Please give me your experience.
Thanks
Pete

If you have aluminium cable then you need to look for corrosion, especially at accessories, dissimilar metals.

You will have to be extremely carefull when moving the conductors as the cable becomes incredibly brittle.

I might be wrong but I think the conductor CSA was increased to compensate for the lower current carrying capacity compared with copper?

 

[Chr!s]

Are you sure its not tinned copper

 

[Piratepete]

Are you sure its not tinned copper

Interesting question. Customer said it's alu but I did think the cores looked very shiny for alu. Will check.

When was tinned copper used for domestic wiring and why?

 

[telectrix]

60,s and 70,s tinned copper was used. earlier stuff was stranded . don't ask me the why, though.

 

[Knobhead]

If it is aluminium you will soon tell if you cut it. All connections should be coated with anti-oxidant paste or Vaseline to protect them. Denso used to make a paste called Densall but I’ve not seen it for years. Don’t over tighten screw connections as you can squash the wire until there’s nothing left.
For Christ’s sake don’t do what one numpty I worked with did. Copper slip! “Well it’s grease, it’s what I’d got with me”, it rots aluminium in hours. Newly connected 70mm cable burnt out in ½ a day.

 

[PC Electrics]

The last lot of ali wiring I came across (4 weeks ago) I checked the csa and it was the same (ie, 1.0, 1.5 and 2.5). The ccc is approx 0.75 that of the equivalent copper.

Careful with the connections, easy to squash the wires too much.

 

[UNG]

All connections should be coated with anti-oxidant paste or Vaseline to protect them. Denso used to make a paste called Densall but I’ve not seen it for years.

I use an anti oxidant paste called Penetrox made by Burndy

If you google "oxide inhibiting compound" you will find a number of different manufacturers / suppliers, I have used most of them that are listed in the last 30 years and don't particularly have any preference for one type

 

[Engineer54]

These Ally T&E cables that were brought in as an option to the normal copper T&E cables, were copper-clad so did not suffer from the corrosion bare Ally cables suffer from. The equivalent 2.5mm cable in Ally was 4mm stranded with 2.5 cpc as i remember. Can't remember the equivalent Ally size for 1mm T&E, but if anyone has an early 16th ed or 15th ed there will be cable tables in there giving you that information...

Try spurring off a ring at a socket outlet, ....12mm of cable trying to fit in a 10mm screw secured terminal!!!! lol!!!

 

[Knobhead]

It wont go down well with the customer but if turns out it is aluminium cabling, recommend a rewire. Aluminium is a boggy man waiting to bite.

I’m a member of an international board for engineers. It seems that some American states are insisting on rewires following several fatal fires.

As to over tightening terminals, one plant I worked on had problems with motor and isolator terminals burning. It took a while (years) to sort out what was happening. As part of the shut down all terminal boxes were checked, one of the lads insisted on tightening the terminals. You can keep tightening aluminium until there’s nothing left of it!

 

[ian.settle1]

Aliuminium cables was used a lot in the 70's as the price of copper went through the roof but since then research found it was not suitable for small sized cables thats why you can now only get it from 16mm upwards.

 

[telectrix]

Aliuminium cables was used a lot in the 70's as the price of copper went through the roof but since then research found it was not suitable for small sized cables thats why you can now only get it from 16mm upwards.

don't think i'd like to attempt getting 2 x 16mm in a socket terminal. LOL.

 

[Engineer54]

I've always considered Aluminium cables as false economy, too many disadvantages as apposed to the few advantages....

 

[malcolmsanford]

I've always considered Aluminium cables as false economy, too many disadvantages as apposed to the few advantages....

Don't know I always thought the nice pyramid shape of the conductor was quite smart .................