Can I use a 4mm T&E for a 7.5Kw shower?

[louis butler]

The cable is installed in 3 metres of trunking, 3 metres clipped direct, and 5metres in the joist space with no insulation,

 

[Davey251086]

Don't they run at full load continuous on full power ?

Or am I missing something ?

Good question, think theres loads of factors like how hard the water is, limescale, how cold the water is, how loose the connections are to how much juice these bad boys need to perform at the right temperature.

Like a cold frosty day on an old shower with hard water surely its full load constantly.

Be one for the manufactures that one as its the appliance that determines the load required to do its job.

Id say same as james.

You could always put a clamp meter on wack it on full power and watch what happens on a cold day vs a hot day e.t.c.

But im sure we all have better things to do ?

 

[Mikegh]

What's the biggest brand in the UK then

Triton seems to be rated higher than Mira here and there was load of problems with the Mira qt apparently

I usually take away the old elite 2 and ST when fitting a shower to keep for my own place, they don't give much trouble

Load of spares I can't be doing with paying for showers for myself

 

[Davey251086]

What's the biggest brand in the UK then

Triton seems to be rated higher than Mira here and there was load of problems with the Mira qt apparently

I usually take away the old elite 2 and ST when fitting a shower to keep for my own place, they don't give much trouble

Load of spares I can't be doing with paying for showers for myself

What's the biggest brand in the UK then

Triton seems to be rated higher than Mira here and there was load of problems with the Mira qt apparently

I usually take away the old elite 2 and ST when fitting a shower to keep for my own place, they don't give much trouble

Load of spares I can't be doing with paying for showers for myself

I think mira and Triton are both very good recognised brands but for me neither.

You cant best a mixer shower the flow rate is so much better. Id all always pick thst set up anyday.

Ive got a mira digital mixer at the minute. Got the best of both worlds i feel.

 

[chris murphy]

And what is wrong with filling a bath from the hot tap only, if you have a combi boiler? Surely it's more ridiculous to use large amounts of gas to heat the bath water, and then turn the cold tap on just to make it cold again?

Hello wigwamabama,

I worded that part of my reply to telectrix badly - what I was trying to describe was that the temperature rise from the very cold incoming Mains water was so poor that the people had to get into the Bath almost the minute that the Hot water from the Combi Boiler was run into it or it would have gotten too cold to bathe in.

Chris

 

[johntheo]

Good question, think theres loads of factors like how hard the water is, limescale, how cold the water is, how loose the connections are to how much juice these bad boys need to perform at the right temperature.

Like a cold frosty day on an old shower with hard water surely its full load constantly.

Be one for the manufactures that one as its the appliance that determines the load required to do its job.

Id say same as james.

You could always put a clamp meter on wack it on full power and watch what happens on a cold day vs a hot day e.t.c.

But im sure we all have better things to do ?

There is no difference in the power consumed on a hot vs cold day, you just adjust the "temperature control" which allows more or less water to flow over the heating elements.
You can change the power setting to "eco" which switches off one element, this element is generally but not always a little smaller than the other one so you may get around 60% flow on one element.
Low voltage, because power is proportional to V squared has a marked effect as well, you have no control over the mains supply but ensuring the correct sized cable will give you a 2 to 3V drop. I had, for many years, 243V (230V supply) at the shower terminals with shower running which meant my 9kw shower outputted 10kw.

 

[Petej999]

6mm or above all day long, cable needs upgrading. Even with 6mm cable im still going out to jobs were plumbrrs have fit 9.5kw showers in with burnt up isolators causing tripping.

Don't opperate the isolator under load conditions, use the control on the shower to stop it and switch the isolator off when you leave the shower r\/ bathroom

 

[Davey251086]

Don't opperate the isolator under load conditions, use the control on the shower to stop it and switch the isolator off when you leave the shower r\/ bathroom

No one said they was but i say that to the customer everytime. Its only for emergency use

 

[Davey251086]

There is no difference in the power consumed on a hot vs cold day, you just adjust the "temperature control" which allows more or less water to flow over the heating elements.
You can change the power setting to "eco" which switches off one element, this element is generally but not always a little smaller than the other one so you may get around 60% flow on one element.
Low voltage, because power is proportional to V squared has a marked effect as well, you have no control over the mains supply but ensuring the correct sized cable will give you a 2 to 3V drop. I had, for many years, 243V (230V supply) at the shower terminals with shower running which meant my 9kw shower outputted 10kw.

Interesting, i understand how a shower works but surely the element has to work harder to heat colder water same as a kettle as thats all a shower is just alot bigger version. If you have really cold water your kettle takes longer to boil.

The question to answer further above was does an electric shower run on full load constantly??

I dont believe it does because of the factors listed above.

What do you think??

 

[telectrix]

No one said they was but i say that to the customer everytime. Its only for emergency use

what use is that? you fallover in the shower, how you going to reach that pull cord 6 feet away and 4ft/above .?

 

[Mikegh]

Interesting, i understand how a shower works but surely the element has to work harder to heat colder water same as a kettle as thats all a shower is just alot bigger version. If you have really cold water your kettle takes longer to boil.

The question to answer further above was does an electric shower run on full load constantly??

I dont believe it does because of the factors listed above.

What do you think??

Kettle has to raise water to boiling point so colder water takes longer

Shower is just instantaneous heater ,turns on and heats what passes through it

 

[Mikegh]

Interesting, i understand how a shower works but surely the element has to work harder to heat colder water same as a kettle as thats all a shower is just alot bigger version. If you have really cold water your kettle takes longer to boil.

The question to answer further above was does an electric shower run on full load constantly??

I dont believe it does because of the factors listed above.

What do you think??

Shower runs on half/full load constantly as well

It'll change temperature if flow changes or may even cut out

 

[johntheo]

Mine (mira Sport) cuts out at 48C if flow of water too low, it also has a non resettable hi limit stat that cuts out the power permanently at a much higher temperature, these two stats are combined in one which is known as a TCO.

 

[johntheo]

Should also have added that you will hear the TCO clicking off approx 15 secs or so after switching off the shower as there is alot of residual element(s) heat still present when the flow of water ceases.
Some showers also have a phased shutdown where the elements power is switched off ~ 10 secs before the water is shut off, its claimed that this helps to prevent limescale build up on the elements in hard water areas.

 

[Davey251086]

what use is that? you fallover in the shower, how you going to reach that pull cord 6 feet away and 4ft/above .?

? whats it going to help if you fall over in the shower switching off the isolator.

 

[Davey251086]

I love these convos you have to put every detail in about every product or operation. The science behind it or the physics, the calculations like you designing an electrical installation right from your phone.

If you put anything in laymans terms someone is quick to point out a fall or bite ?

Have fun guys another forum i wont be on again.

You lot are way better electricians...well done