infra red heaters- any ideas

[johno]

good evening everyone, got a call to check 2 heaters, 4 installed years ago, 2 on 20a,m9 type b breakers and 2 on 16a m9 type b, one of each is tripping when turned on, other ones are ok, is it just the breakers giving up with the load of 3000 w kicking in. both heaters are within 5 meters of the dist board,

 

[batty]

Johno is that 3kw per heater or 3kw for two heaters.

Batty

 

[johno]

3kw per heater, i think, nearly sure, they are all on separate 2.5 radials, 3 are fitted with pirs, 1 of those is ok , just 2 others tripping the mcb when coming on, then someone switches the mcb on its ok.

 

[batty]

It sounds like overload 3 kw is 12.5 amps so two times that is 25 amps.

Battyl

 

[johno]

only 1 heater on each mcb, i can`t find a pic anywhere but almost positive 3kw,

 

[Mr Sworld]

Possible inrush currents if the heaters are only tripping out when cold. Could try type-c mcb's to see if it cures the problem.

Are all the 20A and 16A mcb's from the same manufacturer?

 

[johno]

going to try type 3, all mcbs are bill type b`s at the minute, possibly fitted 15 years ago, not a make i have fitted before, the same as mem i think, thanks for the answers i`ll let you know how i get on later.

 

[johno]

just an update, changed the two 3kw heaters onto different 20a type b mcb`s , everything ok when tested, and working, call today, back to tripping, then informed, "they have been doing that for 1 1/2 years..... super.. how do you post the smily things at the side, i`m pull my hair out..