Discuss Oven cable melted cable and casing - can't work out why in the DIY Electrical Advice area at ElectriciansForums.net
When two things touch, only a very tiny area of material makes contact - the rest of the surface is separated by a thin film of air / grease / tarnish. An electrical connection needs a minimum cross-section of copper-to-copper contact to carry the current, just like a cable needs a minimum cross section. When you clamp a terminal tightly, it squeezes out air and moisture and dirt as the metal cold-flows into position. Only once that has happened is the contact area large enough to carry the current involved here.
You have also, I think, not recognised that the terminal type requires a fork termination to be made, whereby the strands of each live conductors are separated to form two similar prongs, which are then inserted left and right of the nut and bolt, thereby maximising the amount of surface area in electrical contact. You have simply inserted to one side of the nut and bolt.
The connection was insecure and of high resistance; the heat has melted the plastic housing and probably allowed the terminal to short-circuit to the metal casing. It's not clear whether your side of the connection was at fault or the internal one(s) hence Marconi's question. From the pattern of burning, I think it's your connection.
Common causes are crossed threads - the nut feels tight but isn't clamping the cable or cable not in position so that it creeps out from under the washer. Did you give it a good tug-test after fitting?
Reply to Oven cable melted cable and casing - can't work out why in the DIY Electrical Advice area at ElectriciansForums.net
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