What size thread for Immersion Heating Element?

[Tony Griffin]

Hi, I want to fit an immersion heating element to my hot water tank (water is currently heated by gas). I'd like to buy it before I start draining water from the tank. The plug in the tank has a 1 1/4" nut on a pate approx 3" in diameter, does anybody know what size thread the tank will have?
Are there any elements less than 3KW - I have solar panels so I'd prefer something less than 3KW if possible.

Thanks in advance,
Tony.

 

[ShaunCorbs]

Any chance of a picture of the plug ?

 

[king of pipes]

It's a 2 1/4"bsp thread 2kw immersion heaters are available a quick Google search will point you in the right direction. Kop