Patio Heater problems grrr.:-((

[madmatt]

Hi everyone just wondering if anybody has had any problems with the red halogen style garden heaters as have just been called to a house to look at some that a previous spark fitted two of them were 2 kW each and fed looped into a ring main thru 20 amp d.p. switches. these seem o.k. but the one fitted on the garage is not having any of it !!
Its a funny set up as there is a 16 amp crabtree mcb feeding out to the garage not as expected on an s.w.a. underground but on a small pyro cable into another board which is an old Wylex effort, the problem we have is that as soon as you switch the d.p. that feeds out to the 3kW heater it instantly trips both the 16 Amp Wylex mcb and also the mcb indoors at the main board also a 16 amp !

I was just wondering if the 3kw heater maybe starts up with a bit of a surge or something enough to trip out the breakers as the pyro should be man enough to handle the 13 Amps or so load on it ...

Anyone got any ideas, any help would be well appreciated....
Matt..

 

[DadofTwo]

First instinct says incorrect wiring. Reverse polarity, shared neutrals or fault to earth. Have you checked the wiring behind the DP switch and at the heater itself? Can you check the entore run of cable between switch and heater?

Guessing you've checked this already although you've not mentioned it.

Regards

 

[Ross Trician]

Hello Madmatt,
I had a similar problem with 4 infrared type heaters (if infrared is the correct term). these were installed as part of a rebuild/refurb after a fire in our local scout hut. (not me who did the work) as soon as they were switched on at the FCU they imediateley took out th CB. it was a Type b, 16A.
I contacted the makers of them and came to the conclusion it was due to the load surge on start up. I changed them to Type C and these have worked very well since.

 

[madmatt]

Cheers guys and yes Ross that was the problem I went back armed up with a polestar "C" type 16 Amp and that held the load fine, I then swapped out the Wylex cb for a lawson type cartridge fuse that pushes directly into the wylex fuse way and are rated as a C as opposed to being a B type that the switch type cb's are.. when I put my fluke clamp on upon start up for a second the load shot up to 22-23 Amps !! no wonder it was popping the B16 !
Even though the manufacturers insisted no surge on start up ! then obviously dropped back to 12.5 ish Amps and as low as 10.5 A on running load... Thanks for the help Guys... Matt.