immersion heater element failing within 1 year

[robgun]

Hi All, I have a standard 2 element hot water tank. I have replaced the elements on a regular basis ( approx they last 1 year [when 1 goes I replace both elements), we do have hard water, but then again i use the 'Incoloy' types ( which i am told should last a few years)

The top element is powered via a standard 13A fuse / flex which is plugged into an extention. I'm no electrician & I’m sure this isn’t 100% correct, BUT, when the elements work they work fine ( ie no power tripping / blown fuses ) BUT can anyone offer any explanation as to why my elements ‘go’ so quickly???
rgs rob

 

[kai]

What are the power rating of the elements?

 

[robgun]

both are standard 240V 3kW elements

 

[plugwash]

are you replacing just the elements or the entire heaters? I wonder if the problem is with the thermostats causing the water to get too hot and greating increasing the rate of limescale buildup.

 

[robgun]

i replace the element & themostat, as they usually both come together anyway.

Originally i thought it was the build-up of scale ( due to hard water) but as they still 'go' ( even though i'm using better quality elements) i'm thinking its more to do with the electrical side??