Electrical wire

dunnyrail

DOGS, Garden Railways, Steam Trains, Jive Dancing,
25 Oct 2009
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St.Neots Cambridgeshire UK
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They are OK on NEW wire..

If you are trying to do a repair, then you will find the wire strands will probably have tarnished, and these may not get warm enough for any flux-component to 'burn-off' the oxidation.

PhilP.
Indeed so, but well worth thinking about for new installations for those that are a little timid about soldering outside.