bathroom pull switch

[luca]

hi , i am replacing a bathroom pull cord switch because of a faulty pull switch, the old light has 2 N and 2 L and they are 2 grey mains cable coming from the ceiling each with a black , red and a bare wired i assume is earth , when i took the old switch off the 2 black and 2 red were joined into the 2 N terminals, but the new switch has a L and a COM and every time i try it the fuse blows , i have tried every way i can think of and either the light does not come on or it blows . If i put the old switch back on the light works fine but ihave to loosen the casing down for the pull switch to work which exposes the wires . someone please help cos i am completely stuck. ta luca

 

[Spark123]

It sounds like the old switch is a double pole, is there a fan connected to the circuit? If not, see:
//www.diynot.com/forums/viewtopic.php?t=49509.
If there is a fan and this switch is used for isolation it should be replaced with a double pole pullcord.

 

[luca]

cheers bud joined two blacks with terminal block and a red in L and COM and hey presto it works, thanks for your help . luca