100w bathroom light fitting why is the terminal connection block getting hot and melting the plastic covering screws are all tight thank you?

Answer 1

The first thing you do is buy a new lamp holder and install it. Hot terminals are not good and can cause greater problems down the road. It is probably the neutral (white) terminal that is the offending one. There is a small aluminium rivet that connects the lamp shell to the screw terminal. The off and on operation of the lamp heats this component and causes expansion and contraction. Over a period of time the connection becomes loose and starts to arc. This arcing causes the heat. When these types of keyless lamp holders first came out, all of the parts were made of brass and were of a better quality. Cost cutting caused the use of aluminium to be used and you see the resulting. One thing that did come out of the cost cutting was these lamp holders became a cheap throw away item and cheap to replace.