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An ugly but working HP6060B Electronic Load
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AVGresponding:
Al oxidises very aggressively, hence its use as the "fuel" in thermite. It does not need to be damp; that's only a factor in galvanic corrosion.
AMR Labs:

--- Quote from: AVGresponding on January 25, 2023, 06:40:35 am ---Al oxidises very aggressively, hence its use as the "fuel" in thermite. It does not need to be damp; that's only a factor in galvanic corrosion.

--- End quote ---

Yes I agree its a product of galvanic corrosion, but damp or wet surfaces are better conductors than dry, so the galvanic process is accelerated which in itself at the end is a flow of electrons between two dissimilar metals, hence electrical current.
AVGresponding:

--- Quote from: AMR Labs on January 25, 2023, 02:20:40 pm ---
--- Quote from: AVGresponding on January 25, 2023, 06:40:35 am ---Al oxidises very aggressively, hence its use as the "fuel" in thermite. It does not need to be damp; that's only a factor in galvanic corrosion.

--- End quote ---

Yes I agree its a product of galvanic corrosion, but damp or wet surfaces are better conductors than dry, so the galvanic process is accelerated which in itself at the end is a flow of electrons between two dissimilar metals, hence electrical current.

--- End quote ---

Yes, but my point is that Al will oxidise in a completely dry environment.
jwrodgers:
(UK electricity distribution referenced...)
I have experience in electricity distribution systems, particularly in low-voltage power at 400/240 V. In modern systems, most cables are made of aluminium and have a cross-section of 300 mm2. These cables are terminated at low-voltage fuse panels and down the feeder near properties have service joints that connect them to copper or Al cables to take the power into houses.

Connections at the source end are usually made using clamps with a bolt that shears at a specific torque. Based on my experience, these clamps are more than capable of carrying 400 A without causing issues. Any oxidation or resistance buildup could generate significant heat. Therefore, aluminium as a conductor is suitable, as long as the contacts and terminations are clean and bright during connection.

btw... all good conversation :)
AVGresponding:
The only Al conductors I've seen in mains supply have been ones we're ripping out, that were fitted decades ago   :-//

Though I'll grant you, the biggest supply I've worked on was 270mm2 4C Cu x2, fused at 1250A/ph before we replaced the panel board, and incomer from the substation.

The biggest Al cables I've seen, probably a decade ago, were no bigger than 120mm2 or so, one particularly ugly one being a 2C quadrant cable, with half-moon cross sections. No way you're terminating that into a regular crimp, which means, as you say, an adapter with a shear bolt for each conductor. All that adds size as well, which in todays penny-pinching boards that are ever reducing in size to save on materials, is yet another disadvantage. These were used to supply various DBs from a main panel board at a municipal swimming pool, and were all replaced with nice Cu cables.
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