door bell circuit testing help and advice wanted

[olsonn]

Come across something today that I need some help with. The circuit starts off in the CU using 1.0mm T&E on a 6amp MCB and it then goes into a transformer outside of the CU. On the other side of the transformer is 2 core bell wire which not only supplies the front door bell, it also operates the old style servants bells. What I don't know is how am I suppose to test this circuit and what tests I should do. Any help really appreciated

 

[nikmet]

Press the button?

 

[olsonn]

I pressed all 5 and they all worked, but I still don't know how to test them

 

[telectrix]

what testing are you performing? is it a PIR?

 

[olsonn]

I am putting in a new CU so I have to test every circuit. The doorbell was in the old CU so I want to reconnect like for like.

 

[Philintheblanks]

Presuming it is a 220-240v primary & 12v or similar secondary transformer, and the fact that this is installed externally to the consumer unit your obligation ends with testing the supply cable feeding the Primary side of the transformer and record the results as you would for any other fixed load.

 

[Engineer54]

Surely, if as you say it is working before you do the CU change, then it will work after the change. All you can effect by getting anything wrong, will be to the Double Wound Tranny. Everything after the tranny, will be physically isolated. What do you envisage, that could go wrong with this door bell and old servants call bells by changing the existing CU??

 

[Mark_Burgess]

Test as usual the circuit up to the transformer(as if it were a shaver socket), then as the rest is DC it could be classed as the bell equipment.

 

[Engineer54]

DC?? You sure??

 

[Philintheblanks]

Test as usual the circuit up to the transformer(as if it were a shaver socket), then as the rest is DC it could be classed as the bell equipment.

Is it DC?, it will still be AC on the secondary side if its just a standard bell transformer. Agree with your comment though test up to transormer primary side is all that is required during a CU change.