reversed polarity

[wolfiehogan]

went to add a socket to a circuit the other day and when testing found that the circuit had reversed polarity, i taught this would trip the rcd but it didn, so does reversed polarity mean the rcd wont trip under a fault

 

[derek preece]

The most important thing is the appliance “live” isn’t fused with reversed polarity. The only protection would be a 30A fuse or MCCB back at the board.

So you're saying that the appliance/plug fuse becomes effectively useless as it only stops the connection with the neutral but the appliance itself could remain live if the circuit breaker doesn't trip?

 

[ezzzekiel]

on the bigger picture supposing the cross was at the incoming, take pme which shares a common earth/neutral path now all earthed pipework etc would reach live potential as well

 

[Knobhead]

So you're saying that the appliance/plug fuse becomes effectively useless as it only stops the connection with the neutral but the appliance itself could remain live if the circuit breaker doesn't trip?

You got it!