communal lighting , contactor

[glasgospark]

got a 240v ac set up for communal lighting in a small block of flats ,

call out was that outside lights not working , the contactor has 25mm incomer from db1 and 25mm outgoing to db2

incoming side also has 1.5mm t&e.


i cant seem to find the operating device for the contactor any suggestions ??

dusk-dawn pir ?

 

[micknew]

I'd be tempted to factor them in if the voltdrop became unacceptable/ < manufacturers spec during start-up.

unnecessary honest.

 

[glasgospark]

Does the contactor bring in a DB, hence the 25mm tails?

it does yes but the db only has 3 ,6 amp circuits on it nothing overly large loading wise

 

[micknew]

it does yes but the db only has 3 ,6 amp circuits on it nothing overly large loading wise

So the 25mm was allowing for future additional loads, not relevant anyway.

 

[glasgospark]

So the 25mm was allowing for future additional loads, not relevant anyway.

well possibly that was entered into it but it would only ever be lighting as the db is controlled via photocell and contactor , personally i cant see the need for contactor

 

[Marvo]

Maybe the load was larger and got trimmed or maybe as Mick says it's future provision but it's a large provision so I'm sure there'd be a definate reason behind it.

Bottom line is regardless of tail sizes it's a very simple circuit. PIR operates the contactor, contactor switches power to DB and brings in the lights. There's numerous ways the wiring could be physically laid out same as there's several ways to cable a normal domestic lighting circuit.

 

[jay sean]

faulty device controlling contactor then?

 

[glasgospark]

i think the pcell is faulty yes but , does the photocell in this case simply have live in and live out

 

[Marvo]

.....personally i cant see the need for contactor

Pleeeeese don't remove the contactor. The SON lighing load is probably far from linear plus there's start currents to consider, I doubt the PIR is rated to switch the load directly. Just fault-find the existing setup and fix it. If you alter the circuit make sure you have a design that you know is viable because it will be your responsibility if you do.

 

[Marvo]

.....does the photocell in this case simply have live in and live out

Your asking me? I'm in Cape Town....you're the one that was on site....

 

[glasgospark]

Pleeeeese don't remove the contactor. The SON lighing load is probably far from linear plus there's start currents to consider, I doubt the PIR is rated to switch the load directly. Just fault-find the existing setup and fix it. If you alter the circuit make sure you have a design that you know is viable because it will be your responsibility if you do.

i have bypassed the contactor for now , feeding the db from a 20a mcb with 2.5 t&e untill i can get to photocell ,

its 10meters up

 

[glasgospark]

Your asking me? I'm in Cape Town....you're the one that was on site....

i mean for the fact its a 2core&earth T&E going to the photocell

 

[micknew]

Just to qualify my comment, no need to consider starting current as it only lasts for milliseconds.
Not enough time to cause damage to cable.

 

[micknew]

Faulty photo cell or contactor coil probably.

 

[NJR]

i mean for the fact its a 2core&earth T&E going to the photocell[/QUOTE

Used for live and s/live?

 

[Dcf]

Every photocell I've come across needs a live neutral and switch wire.
is there a slid lock fuse or something that is in circuit to switch the d/b?
as it was quite common back in the day to fuse the control circuit down using such methods.
start there and look to see if the photocell has had it