I visited a client about a week ago, an elderly couple complaining that their lounge, hall and landing lights were all flickering simultaneously with a noticeable buzzing noise. When I arrived the lights appeared to be working ok (I asked them to switch them off until I could attend), so an intermittent fault. Opening up accessories revealed the likely culprit - aluminium conductors, the first time I have come across these.
Some observations:
House built 1973
1mm² (or so I believe, next time I'll measure w/ micrometer) single solid strands
Dull silver appearance, brighter when cut.
Not copper clad aluminium, not tinned copper.
Very soft and supple compared to copper.
Higher resistance values vs copper
Prone to breaking off where screwed at the terminations.
It was hard to get a clean reading by testing continuity with the probe placed directly on the bare conductors (CPCs were unsheathed), the reading would jump around constantly in the range of a couple of ohms. I presume this is due to the insulating oxide layer aluminium is said to form. Clipping a jump lead to the conductor and testing to that gave a steady reading, as did testing to the brass terminal where soundly terminated.
Other circuits in the house are, at a glance, aluminium also.
I did what I could in the time I had available - I went through the circuit (downstairs lights) checking and tightening everything, found several conductors broken or very nearly broken at the screws so reterminated those, and ended up with satisfactory R1+R2 vs RN+R2 results. Borrowed neutral on landing light as you would expect for a property of that age.
Anyway, received another call from them on Christmas eve, they had noticed a small flash and pop! from one of the bedroom wall lights when switched on. Also switching on say the main bedroom light would cause a momentary flicker on the landing lights. He also told me they had an intermittent problem in the past with the bathroom light flickering, and certain sockets sparking when switched on. Advised not to use dodgy lights and sockets until I can get to them in a day or 2.
The place is obviously due a rewire, and that's what I will recommend. In the meantime, I'll need to make good any problems. I understand standard accessories are not to be used with aluminium conductors. Apparently some Wagos can be used on aluminium conductors when used in conjunction with the Alu-plus paste:
www.wago.com
I was thinking of using this to connect a length of copper conductor to the ends of the aluminium conductors, then terminating the copper in the accessories. I have reservations though, I suspect the 1mm² aluminium will be too soft and bendy to force into a wago 773.
What have other members of the forum done in these circumstances and what would you recommend? As always, all information gratefully received
Some observations:
House built 1973
1mm² (or so I believe, next time I'll measure w/ micrometer) single solid strands
Dull silver appearance, brighter when cut.
Not copper clad aluminium, not tinned copper.
Very soft and supple compared to copper.
Higher resistance values vs copper
Prone to breaking off where screwed at the terminations.
It was hard to get a clean reading by testing continuity with the probe placed directly on the bare conductors (CPCs were unsheathed), the reading would jump around constantly in the range of a couple of ohms. I presume this is due to the insulating oxide layer aluminium is said to form. Clipping a jump lead to the conductor and testing to that gave a steady reading, as did testing to the brass terminal where soundly terminated.
Other circuits in the house are, at a glance, aluminium also.
I did what I could in the time I had available - I went through the circuit (downstairs lights) checking and tightening everything, found several conductors broken or very nearly broken at the screws so reterminated those, and ended up with satisfactory R1+R2 vs RN+R2 results. Borrowed neutral on landing light as you would expect for a property of that age.
Anyway, received another call from them on Christmas eve, they had noticed a small flash and pop! from one of the bedroom wall lights when switched on. Also switching on say the main bedroom light would cause a momentary flicker on the landing lights. He also told me they had an intermittent problem in the past with the bathroom light flickering, and certain sockets sparking when switched on. Advised not to use dodgy lights and sockets until I can get to them in a day or 2.
The place is obviously due a rewire, and that's what I will recommend. In the meantime, I'll need to make good any problems. I understand standard accessories are not to be used with aluminium conductors. Apparently some Wagos can be used on aluminium conductors when used in conjunction with the Alu-plus paste:
Syringe (249-130) | WAGO GB
Syringe; Contents: 20 ml Alu-Plus contact paste (4017332133890) Online at WAGO GB!
I was thinking of using this to connect a length of copper conductor to the ends of the aluminium conductors, then terminating the copper in the accessories. I have reservations though, I suspect the 1mm² aluminium will be too soft and bendy to force into a wago 773.
What have other members of the forum done in these circumstances and what would you recommend? As always, all information gratefully received
