Patio heater

[grommett]

I just bought a wall mounted patio heater on Amazon advertised as 800w. When it arrived I found it had no rating plate on it. The instruction booklet said 110/230v 800/1500w so I read that as 800@110 and 1500@240. I decided to return the item and although I have been offered a no quibble return/refund, the seller also assured me it is only 800w and the booklet is referring to two models.

to be sure I measured the resistance of the element at 80 ohms, would I be correct in thinking this would draw 3amps at 240v?

TIA.

 

[Harry Bloomfield]

to be sure I measured the resistance of the element at 80 ohms, would I be correct in thinking this would draw 3amps at 240v?

Yes! and 720w

 

[FrodoOne]

However, does not the resistance of a "wire" change when it is heated?
Would the resistance of the "element" change when it is heated and would it be higher or lower when heated to operating temperature?

 

[Harry Bloomfield]

However, does not the resistance of a "wire" change when it is heated?
Would the resistance of the "element" change when it is heated and would it be higher or lower when heated to operating temperature?

It will be nichrome wire and it's resistance will rise as it is heated, but not to any great extent as to affect the wattage.

 

[ericmark]

I see not problem with a wall mounted patio heater, the heater is high enough not to be touched, but when mounted on a metal pole of some sort, the problem is earthing, specially where used near water, for example a hot tub, so the big question is if class I or class II and when looking for "Amazon patio electric heater 800w" it does show a heater, but it does not say if class I or class II on the wall class I OK on a metal pole you want class II if a TN-C-S supply which is the most common supply.

Lawnmowers, strimmers are normally class II even hot tubs often class II, can't believe the advert does not say class I or class II.