Electric shower wiring, does this look ok?

[ebee]

That's easy for you to say.

LOL

 

[EFLImpudence]

 

[SUNRAY]

Yes good point, but I tink that sometimes they are not equal, perhaps intentionally and probably not always. Obviously we can only measure then cold and once warmed up that will vary but it gives us an initial rough idea.
Perhaps they are designed to be based on a logarithmic sort of difference rather than linear but then at least two of them equal to make production runs more economical.
One manufacturer might bias them logarithmic or geometric and another identical , with either 2 or 3 elements, and which one will be more successful?
Difficult to answer, even for them, there are other factors involved with their decision for greater success or less success.
Only hindsight can confirm their decision success/failure/50 shades of grey.
All we can do is make an approx linear guess then see if it appears to be somewhere near considering hot/cool and manufacturing tolerances and see if it tallies .

One reason I noticed these things is to make a water warmer for a handwash in my shed, I had a few different shower units for spare or repair and decided to measure element resistance so I did a quick calc for each different rating then observed measurements.
My intention was to consider altering connections so the elements could run in series rather than in parallel and calculate the expected temperature rise that might be achieved.

Some of you might have insider information that proves me right or proves me wrong!

I assume a 10½KW shower heater has 3 similar 3½KW elements but I've never thought to measure. Personally we use ours on low power as neither of us like it either very hot or stinging pressure.
I've never considered using one for a hand wash but I have fitted several 3KW hand wash units and to put it bluntly they are 5hit, I have fitted one which I think was around 7KW (I used 4mm² and 32A MCB) which was wonderful, in a domestic garage which the owner used all day every day restoring classics, more like a commercial premisis.
Realistically washing hands isn't much of a different requirement to a shower so I very much doubt you'll be wanting to reduced the power by series wiring.

 

[ebee]

Realistically washing hands isn't much of a different requirement to a shower so I very much doubt you'll be wanting to reduced the power by series wirin

Yes, it was just a warming of the water needed and 7 to 10Kw would have been too hot and expensive to run so I thought "hey perhaps two elements in series for quarter power and the testing went from there really, thats when I noticed some differences and maybe more than production line tolerances seemed likely on some, especially the three element variety

 

[SUNRAY]

Yes, it was just a warming of the water needed and 7 to 10Kw would have been too hot and expensive to run so I thought "hey perhaps two elements in series for quarter power and the testing went from there really, thats when I noticed some differences

Realistically to wash hands will require a relatively fixed amount of water, the flow rate from a 3KW heater is so feeble it is likely to be in use for twice as long as a 6KW and suddenly the mathematics kick in.

 

[ebee]

Ok thanks. I just thought I might try if but I never got that water plumbed in.

 

[morqthana]

One reason I noticed these things is to make a water warmer for a handwash in my shed, I had a few different shower units for spare or repair and decided to measure element resistance so I did a quick calc for each different rating then observed measurements.

What was wrong with your first attempt?

 

[SUNRAY]

Sadly I didn't take a picture, before the days of cameras on phones, but a lot of years ago a friend had an unused upright freezer in the garage, in the hot summer he took the door off, cut some holes in a sheet of ply and fitted a couple of ex PC fans then screwed the ply to the garage door from the house and stood the freezer tight against is. The freezer was in the garage so the fans drew the chilled air into the house.
The poor freezer was obviousely working flat out and doing it's best. Of course it was not particularly effective but it did make a difference.

 

[ebee]

I am glad that you posted this picture of this first attempt my friend

I`m glad that, apparently, a number of people put a fridge or freezer in a confined space 9such as the pantry under the stairs and leave the door open hoping it will cool the room only to find that actually it heats the room.

I think that some of us are as stark raving mad as people who try to get rid of acne with sandpaper - why do they do it?

 

[morqthana]

I think that some of us are as stark raving mad as people who try to get rid of acne with sandpaper - why do they do it?

 

[SUNRAY]

I`m glad that, apparently, a number of people put a fridge or freezer in a confined space 9such as the pantry under the stairs and leave the door open hoping it will cool the room only to find that actually it heats the room.

Just in case that's aimed at my post the freezer was in the attatched garage and the chilled air entering the house with the sheet of ply effectively sealing between the house and garage

 

[ebee]

Only in America LOL