We had a cheap Homemaker brand HT7145KM heater come in for recycling.  This one had two of the halogen heating lamps rattling around in the bottom because the ends had shattered and the third on was on the way out as well.  I thought I would take it apart for a bit of a laugh.  And look what I found.

One of the case screws had pierced one of the wires, in this case it was carrying the voltage going to the oscillating motor.  This is pretty poor manufacturing quality to say the least!  Fortunately the screw is recessed about 20mm down a hole otherwise it would be a serious safety issue.

Another worry is that if the wire strands were cut by the screw would the remaining wires have created enough heat to melt and burn the plastic?  Possibly not given that the oscillating motor is quite low current.