Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 17 replies
  • Subscribers 32 subscribers
  • Views 1354 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Wiring 10 vector heaters supplied by 10mm cable.

Former Community Member
Former Community Member
Hi,


Whilst on site a few weeks ago, I noticed an electrician wired 10 vector heaters onto a 10 gangway switch.

​​​​each of the switches turned each of the heater's on. 

however, all these switches were supplied by the 10mm cable I was running above the ceiling tiles. 

Now I noticed each heater had a power rating of 2500 watts, 


So assuming all the heater's were turned on, and given the kind of premises it was, all the heater's would be on if used, that would have been a total of 25000 watts supplied by a 10mm cable. 


I'm just confused as to how he wired it,

Im pretty sure they were wired parralel, as each heater had it's own flex going straight to the switch board. Can anyone can help with a wiring diagram. It's really been bugging me.
  • 0
    The possibility of over 100 Amps load on a 10.00mm2 cable is frightening. Didn't you have a chance to ask the installer about this? Perhaps there were several separate circuits.


    Z.
  • 0
    3 phases at 10mmsq or just one ?


    IF the heaters were split over the 3 phases, so < 50A per phase it would be OK.
  • Former Community Member
    0 Former Community Member
    They were not 3 phase from what I saw. I didn't really get a chance to ask the installer I ran the cable 3/4 of the way, but looking at it from a distance the cable went all the way to the switch and on this 10 gangway plate. 


    The next day once the installer did his work and left, I had a look, each heater had it's own flex going back to the switch plate. 


    ​​​​
  • 0
    So the cable you laid is is 10mm2 and 2 core, single phase - if so then it is undersized.

  • Former Community Member
    0 Former Community Member
    This is what I thought, as well, I'm not at that site anymore. It was definitely single phase, that premises had multiple consumer unit's but no 3 phase board. Before he organized it into a 10 gang switch, they use to be individually powered by a ring circuit. 


  • 0
    I'm confused - 10mm2 supplying grid switches?

      - Andy.
  • 0
    well grid switches each supplying one 2.5kw heater is not too foolish, assuming the grid switches are the right modules (20A anyone) I presume that the 10mmsq has to be split into however many bits of 2.5mm to do its duty, so there was probably another box you could not see  terminating the 10mmsq, and I'd like to imagine, depending on the supply side fusing, maybe some local fusing down to a lower current for each heater.  In any case, the 10mm cable would need protecting by a 60A fuse or something, and then as noted, you cannot have all the heaters on together. Or if you tried you'd be overloading that bit of the circuit. It would have been better to leave some of the heaters on the old circuit.


    In terms of the original question, yes they are in parallel at that point, but the value of the maximum total current has the eyes rolling.
  • 0

    mapj1:

    well grid switches each supplying one 2.5kw heater is not too foolish, assuming the grid switches are the right modules (20A anyone) I presume that the 10mmsq has to be split into however many bits of 2.5mm to do its duty.




    Each strand of the 10 mm into a switch and a loop into the adjoining ones as required?

  • 0
    Well maybe if it is that sort of job, (!!)  but I'd hope that there was some sort of junction box the OP did not realise .
  • Former Community Member
    0 Former Community Member
    From what I remember each heater had it's own fuse switch. And I have no idea about how the 10mm was wired at the switches. All I did as the labourer was pull the cable to him.

Community Rules & Guidelines