**Show Us Your Installs!!!**

[Marvo]

Looks good mate, as I have never heard of it, whats it for? haha!

Not sure either but I'd hazard a guess at lightning protection maybe. Damn neat install though

 

[ChrisElectrical88]

Not sure either but I'd hazard a guess at lightning protection maybe. Damn neat install though

Im not 100% sure myself, its the first time iv ever done it and it was landed on me friday morning, after speaking to scottish power (im not keen on installing things i dont understand), from what i can gather its to connect all metalwork and switchgear together throughout the building. Ill be doing a bit more research over the weekend so im well clued up for when we get another one.

 

[Richard]

Is it a Haz building?

 

[ChrisElectrical88]

It's a Scottish power secondary substation 33kV I believe but not sure as the LV install and ally tape were as far as I got before they snapped the padlock on.

 

[Bobster]

It's just there to bond all metal work together, quite common in HV substations.

 

[Marvo]

It's a Scottish power secondary substation 33kV I believe but not sure as the LV install and ally tape were as far as I got before they snapped the padlock on.

Well that's a different story, I thought it was a domestic/small commercial premises but it makes sense in a sub station.

 

[Knobhead]

It's a Scottish power secondary substation 33kV I believe but not sure as the LV install and ally tape were as far as I got before they snapped the padlock on.

Cheapskates, copper tape looks better.

I must have used miles of copper tape in both MV substations and LV switch rooms. Lovely stuff to work with.

We couldn’t use aluminium tape due to the chemicals we made, it rotted it away.

 

[Bobster]

Thing is Tony I bet the difference in price is negligible, what with the fact of needed larger aluminium bars. Plus having terminations to deal with the different metals.

 

[Knobhead]

Our problem RoB was the product would attack aluminium. I had a switchboard lying idle for six months, when it came to connecting it the aluminium bus-bars looked like they had been shot-blasted.
The connections had to be coated with Densal antioxidant paste to protect them from attack and galvanic corrosion.

Aluminium ladders were not allowed on plant in case the product got inside the rungs and rotted them.

 

[Jamiemfc]

I believe that Scottish Power are now moving to aluminium for all there cabling also due to the high price of copper, was on a H.V course at there training centre a few months back and thats what the instructor was saying.

 

[ChrisElectrical88]

It was specified by the client. Hopefully at some point I will get to have a god at the copper stuff, we have a full 40m roll in the stores just waiting to be used.

 

[Knobhead]

I believe that Scottish Power are now moving to aluminium for all there cabling also due to the high price of copper, was on a H.V course at there training centre a few months back and thats what the instructor was saying.

They’ve been using it since I were a lad.

I went to EMEB’s training collage about 30 years back. They had us jointing Al to Cu 11KV cables.

 

[ChrisElectrical88]

I heard about the jointing off my gaffer, would love to have a go at it. Do you still attach a mould full of power to it and set it off? Substations and HV is something I'm really interested in. Looking to get on a few courses.

 

[Knobhead]

You’ve got you’re wires (tapes) so crossed I don’t know were to start.

Thermic welding is used for joining the earth tape or cable to an earth mat, especially if you have an Ufer earth.

Use that in an 11KV joint and you’ll be looking for the remains of the cable cores.

Forget any idea of going on a HV jointing course unless you’re company will pay. It’s very expensive and the real knock back when you look at the prices is in small type (plus material costs). £700 last time I looked for a PILC joint kit. You will do more than one joint on the course.

 

[Engineer54]

Yep, this is a standard requirement for sub-station rooms/buildings. Never, ever seen this done in aluminium though. That is possibly going to create more problems than it's initial cost reduction!!

Normally the two ends of this room loop would connect to a MET/MET earth bar, with removable links to facilitate testing. One section of the earth bar would connect all the earthing conductors, such as earth rods, Ufer earth mat, etc, and a second section would contain electrical links from cables TX, switch boards etc. The tape would be used to locally connect and equalise other metal structures or componants within the room, like the metal doors, windows (if any) ventilation louvers and other metallic plant, like AC units and/or it's ducting etc....

 

[ChrisElectrical88]

Yep, this is a standard requirement for sub-station rooms/buildings. Never, ever seen this done in aluminium though. That is possibly going to create more problems than it's initial cost reduction!!

Normally the two ends of this room loop would connect to a MET/MET earth bar, with removable links to facilitate testing. One section of the earth bar would connect all the earthing conductors, such as earth rods, Ufer earth mat, etc, and a second section would contain electrical links from cables TX, switch boards etc. The tape would be used to locally connect and equalise other metal structures or componants within the room, like the metal doors, windows (if any) ventilation louvers and other metallic plant, like AC units and/or it's ducting etc....

We're hoping to have a few more of these of the back of this then doing them quite regular if everything goes ok. Will be interesting to see if the other ones we do are aluminium or copper tapes.

 

[Engineer54]

We're hoping to have a few more of these of the back of this then doing them quite regular if everything goes ok. Will be interesting to see if the other ones we do are aluminium or copper tapes.

Well you won't be able to fabricate bends around the doors etc, as you have done in this case with aluminium. You'll have to use copper tape fittings similar to that used in lightning protection systems.

To be honest, i really can't see why they have specified Aluminium tape, i can see all sorts of problems arising in the future, high resistance joints being just one of them, caused by corrosion/degradation of the aluminium, especially where any dissimilar metals are involved. I'm just wondering if they will install a Copper earth bar separate from this equipotential tape for all the other electrical earthing connections and connecting your tape to that, via a linking conductor?? Who knows, certainly not how i would have specified this installation anyway!! lol!! Copper rules in substations, and for very good reasons!!

 

[Outspoken]

I have to agree with E54 here, I have completed installs in numerous primary and secondary subs over the years and have only ever used Cu tape, never Al.

For me one of the issues is that they are clearly relying on atmospheric Oxygen to react with the tape to create a protective coating of AlO[SUB]2,[/SUB] and this raises all kinds of potential issues at joints because if any of the Oxide gets into the joints the risk not only of a galvanic reaction[SUB],[/SUB] butthe impedance of the joint could become a serious issue as AlO[SUB]2[/SUB] is non-conductive and can cause serious degradation of the joint....hence all joints need to be 100% and they need to be protected with a non-conductive, non-reactive substance, such as grease or petroleum jelly.

Aluminium is horrible stuff for electrical work!!

 

[Knobhead]

Look at the DNO’s current specifications for substations. Aluminium is permitted for earthing.

Not saying I like it, but it’s permitted.

 

[Engineer54]

Look at the DNO’s current specifications for substations. Aluminium is permitted for earthing.

Not saying I like it, but it’s permitted.

It wouldn't surprise me at all Tony!! It seems like everywhere else in the UK, the accountants are taking over Engineering decisions!! This could be yet another mistake, very much like the use of 3 1/2 core cables in the past, to save a bit of money on they're extensive LV network installations.... Only time will tell if the use of Al on sub station earthing will also come back and bite them hard on the arse!! ...lol!!