Brass Glands & Aluminium Gland Plate

[alanElec]

Hi all,
I have a simple but important question.

Can we use Brass Glands for Aluminum Wire Armoured SIngle Core Cables ?? The gland plate material is Aluminium.

 

[waross]

Yes. If the glands are subject to rain or water it is well to paint them with a glyptol type paint.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[alanElec]

Dear Waross,
Thanks for your reply..But i missed your point completely regarding glycol paint. Hope thats a joke..!

1.Tha Switchgear Panel gland plate is aluminium.My cable is 1cx630 sq.mm,AWA 3 runs per phase. I'm planning to use Brass Cable Glands for this cable.I will be running these cables in trenches in trefoil formation.However the Cables will be terminated linearly in the Switchgear.
Here they say we can use brass as well as aluminium glands.But the cost and delivery period for aluminum glands is almost double that of brass glands.

I would like to know if there is any technical issues for using Brass gland in the above scenarios.

Thanks,
Alan

 

[ScottyUK]

I agree that brass glands can be used. Bill probably meant Glyptal, which you mis-read as glycol. If the glands get wet then there is the possibility of a galvanic corrosion cell being formed if there are ionic contaminants in the water. Keeping the joint dry by, for example, use of a coating prevents this problem. If you are indoors then the problem shouldn't exist.

Aluminium glands gall up over time and are a maintenance nightmare if you are anywhere near a marine or coastal area or have any atmospheric pollution.

 

[waross]

Yes glyptal. Thanks Scotty. Last week I got the two mixed up the other way around.
Rain water is no longer pure, acid rain is common. Acid rain on copper may form copper salts that are corrosive to aluminum. In a distribution system with aluminum conductors running from pole to pole it is common practice to position the copper cable drops from the transformers under the aluminum cables, even though it may look neater to position the copper above the aluminum. Some years ago our little island utility was constructed with the copper drops positioned above the aluminum cables. Corrosion and smoking connections were a chronic issue. A visiting utility engineer gave us a tip and the connetions were changed to position the copper below the aluminum and the issues went away.
In the part of the petro-chemical industry that I am familiar with, copper grounding conductors are run in the cable trays and are connected to the aluminum alloy trays about every 12 meters. The connections are then painted with glyptol paint.
Bras and aluminum, I'm not sure, but if it was my installation I would look for some method to avoid rain or moisture from contacting the brass.
If this is an indoor installation with little likely-hood of condensation or moisture the brass glands will not need protection. (Subject to Scotty's comment re marine or coastal areas.)
Ps Check the locknuts. I have seen issues where aluminum connectors were used with ferrous locknuts. The AHJ demanded that the ferrous locknuts be changed out for non ferrous locknuts.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[alanElec]

Thanks both of you..I do not think there could arise a problem of rain or moisture since we are talking about a remote Petroleum Development area in the Middle East(Middle of the desert).Also this one is for a Chiller Plant for Accomodation blocks with little possibilities for contaminants,acid rain,chemicals etc.

 

[Scapper78]

One alternative to this could be the use of an insulated cable gland:

http://www.etscc.co.uk/catalog/cable-glands-adaptors-reducers/insulated-cable-glands

They ensure that there is no contact between the cable gland and the gland plate. This would help to eliminate over heating in the cables as any potential for circulating currents would be avoided. They would need, however, to ensure earth continuity provision is catered for in some form when using insulated cable glands.

 

[waross]

Scrapper78, That would go well on the load end of the cables with standard grounding glands on the feed end.

Bill
--------------------
"Why not the best?"
Jimmy Carter