polarity of heater tapes ?

[astronymonkey]

Hi all,

I have a few heater tapes from kendrich and astrozap and I need to shorten the leads to tidy up the wiring. Is there any particular polarity I need to stick to with regard to which wire goes to the centre lead or isnt that important with these tapes. I know the 4 way controller will have a particular centre pin polarity but does it matter which wire in the tape lead is connected to this ? Cheers

 

 

[spaceboy]

My guess is they are centre positive as this tends to be the rule of thumb with most things. Easy to figure it out though as you will be cutting the cable to extend it all you need is a multi meter or small bulb (indicator bulb out of car) and a battery. Make a circuit so the bulb will light then break the circuit and place the break on the centre pin of the phono plug and the other end on the red wire to be extended. If it is centre positive the bulb should light. 

[Pompey Monkey]

1 hour ago, spaceboy said:

My guess is they are centre positive as this tends to be the rule of thumb with most things. Easy to figure it out though as you will be cutting the cable to extend it all you need is a multi meter or small bulb (indicator bulb out of car) and a battery. Make a circuit so the bulb will light then break the circuit and place the break on the centre pin of the phono plug and the other end on the red wire to be extended. If it is centre positive the bulb should light. 

I don't see how this tests any polarity issue.

 

The active elements in heater tapes are just lengths of resistive wire: "nichrome". The polarity does not matter.

Having said that, keeping to a standard will do no harm whatsoever.