Help on lighting fault

[Rob678]

Advice required please guys.
Currently doing my electrical apprenticeship and encountered a fault today with my colleague at work which left me abit stumped. Customer had tried to change a light fitting and “just put all the blacks together” apparent that one of these blacks was in fact the switch line.
However after it was completed the 2 way hall light operated as expected, however when you turned on the bathroom fan isolator or pulled the bathroom light switch pull cord the hallway light came on or started pulsing ??
Any advice on why this has happened would be great. I feel like it has something to do with the neutrals but I’m not 100%
Thanks in advance guys

 

[littlespark]

If the hall light is LED, then the pulsing indicates a very low voltage going across it…

Rather than us guessing what it might be, I’d be inclined to just disconnect the suspect light, and test every cable to work out what should go where.

 

[Rob678]

If the hall light is LED, then the pulsing indicates a very low voltage going across it…

Rather than us guessing what it might be, I’d be inclined to just disconnect the suspect light, and test every cable to work out what should go where.

My thinking, I potentially thought maybe the bathroom fan and bathroom light had been connected in series with the hall light causing the pulsing and dimness once turned on. Thankyou for your reply

 

[littlespark]

that would do it, as the voltage would be split between the 2 lamps...

You need to identify which black should be the switch wire....

 

[davesparks]

After creating a loud bang by joining all the reds and blacks together the intrepid DIYer will do a little research and discover the wonders of three plate wiring and proceed to creatively mess it up in some interesting ways.
Sometimes this will result in more loud bangs, other times they achieve one switch overriding the rest of the circuit and on some rare, special, occasions they manage to get their lights connected in series.

 

[DefyG]

After creating a loud bang by joining all the reds and blacks together the intrepid DIYer will do a little research and discover the wonders of three plate wiring and proceed to creatively mess it up in some interesting ways.
Sometimes this will result in more loud bangs, other times they achieve one switch overriding the rest of the circuit and on some rare, special, occasions they manage to get their lights connected in series.

Not to mention welding switch contacts together and wondering why when they thought they had got the wiring sussed the light will still not switch off!