Hot water shower power

[tamada]

Can someone confirm the correct, minimum wire gauge that is required for wall-mounted hot water shower units? Also advise on the size of the service breaker?

When the house was built maybe 12 years ago, I had installed a couple of Panasonic 3kW units that work well but never made really hot water like I've experienced with similar sized units in hotels or friends homes. I even upgraded one to a 4kW unit but it is only marginally hotter. However, at this time of year, the smaller one struggles to even take the chill off!

I suspect the sparky short-cutted (evidenced by subsequent discoveries over the years!) so I am making up a list for the prospective 2020 electrical overhaul and need to know if replacing the wiring will sort the problem.

Ta
tam

[kopkei]

we did have such a water heater in our former home , if you use 2.5 sq/mm wire it will be able to handle 4.400 W with a 20A breaker , if you go more heavy , you will need the 4sq/mm cable/25A breaker/max 5500A or the 6sq/mm for max 6600A/30A breaker ,all this assuming you are using 220V and automated breakers, single user on the line ....,
the simple explanation, i am sure others will be able to explain this more complicated ...

[tamada]

^ good start, thanks kopkei.

I also have issues in the kitchen when the water heater is on and either the deep fat fryer or the IR oven or my convection oven are turned on at the same time. The 16 A breaker trips I assume the sparky wired all the outlets AND lights onto the same 16A service breaker. I doubt he ran heavier gauge wire to the outlets either.

Looking at my undersized breaker box, it has 6 x 16A breakers and 6 x 32 A breakers. This for a 4 bedroom house with kitchen and lounge and 2 air conditioners. The home did grow 2 extra rooms from the original plans towards the end of construction but the electrician didn't upgrade the breaker box to match. I was away at this critical juncture and inherited the bodge.

[sometimewoodworker]

Can someone confirm the correct, minimum wire gauge that is required for wall-mounted hot water shower units? Also advise on the size of the service breaker?

When the house was built maybe 12 years ago, I had installed a couple of Panasonic 3kW units that work well but never made really hot water like I've experienced with similar sized units in hotels or friends homes. I even upgraded one to a 4kW unit but it is only marginally hotter. However, at this time of year, the smaller one struggles to even take the chill off!

I suspect the sparky short-cutted (evidenced by subsequent discoveries over the years!) so I am making up a list for the prospective 2020 electrical overhaul and need to know if replacing the wiring will sort the problem.

Ta
tam

As mentioned 2.5mm is OK on up to a 4.5kW heater and you can safely use up to a 25A breaker, but on full power it probably will not exceed 20A also your 20A breaker is not going to trip until you are running way over 20A for a short time or much over 25A for an extended period.

4mm (30A breaker) cable is good for 6kW units (they use about 27A) but go up to 8kW and you should be using 6mm (40A breaker) they use 36A

The wiring will not be the limiting factor as to why you are getting cool/cold showers, it’s the delta between your incoming supply temperature and the temperature you want. That is why the showers in your friends houses and hotels seemed to work better, they just didn’t have to increase the temperature by as much.

Our 6kW units are just OK if the flow is very low at this time of year. They can just get water from about 18C to about 37C with very modest flow and 40C with very low flow.

[kopkei]

in our new home the lights and outlets are also combined together , all our lights are led and do not consume much ,and the wiring is all 2.5sq/mm to make it easy , we have a breaker box of 18 breakers ,all 20A ,divided like this
1/ sofaroom
2/ bedroom 2
3/ bathroom 1 and 2 + grundfos waterpump
4/ ferolli hot water tank
5/ living room
6/ refrigerator
7/ bed room 1
8/ aircon 1
9/ aircon 2
10/oven + gas ignition
11/ kitchen outlets (3)
12/ kitchen outlets (2)/hood
13/ pool pump
14/ washing machines /filter home
15/ freezer
16/ kitchen counter outlets (3)
17/ terrace / carport/well pump
18/ aircon 3
as told all the lights are connected at the used room line
so each of the 18 lines can handle about 4400W, not complicated...
all outlets are grounded and protected with a RCBO/63A/ 30mA sensitivity .....
breaker box schneider

as info ....

[sometimewoodworker]

I also have issues in the kitchen when the water heater is on and either the deep fat fryer or the IR oven or my convection oven are turned on at the same time. The 16 A breaker trips I assume the sparky wired all the outlets AND lights onto the same 16A service breaker. I doubt he ran heavier gauge wire to the outlets either.

The circuit should be very simple to diagnose. Just see what goes off when the breaker is off.

Also check the size of the cable coming from the breaker. And if it’s 2.5 mm you can simply replace the 16 amp breaker with a 20 or 25 amp breaker, both of those will be okay and within the specifications of the cable.

While you’ve got your consumer unit open I would also check the sizes of the cables running from the 32 amp breakers, if they are 2.5 mm cables then you really need to replace those breakers with 20 or 25 amp breakers as a 32 amp breaker on 2.5 mm cable is dangerous, if they are protecting 4mm cable then it’s no problem.

[tamada]

..
The wiring will not be the limiting factor as to why you are getting cool/cold showers, it’s the delta between your incoming supply temperature and the temperature you want. That is why the showers in your friends houses and hotels seemed to work better, they just didn’t have to increase the temperature by as much.
..

Good point. The hotel probably has hundreds of feet of internal plumbing and a much larger storage tank that doesn't get as cold whereas the longest run in our place will be maybe only 10 m from the ~4000 liters stored in concrete, well-pipe style tanks.

By the same token, my mates place is a much newer build availing himself of better construction materials and techniques.

Ta
tam

[tamada]

I also have issues in the kitchen when the water heater is on and either the deep fat fryer or the IR oven or my convection oven are turned on at the same time. The 16 A breaker trips I assume the sparky wired all the outlets AND lights onto the same 16A service breaker. I doubt he ran heavier gauge wire to the outlets either.

The circuit should be very simple to diagnose. Just see what goes off when the breaker is off.

Also check the size of the cable coming from the breaker. And if it’s 2.5 mm you can simply replace the 16 amp breaker with a 20 or 25 amp breaker, both of those will be okay and within the specifications of the cable.

While you’ve got your consumer unit open I would also check the sizes of the cables running from the 32 amp breakers, if they are 2.5 mm cables then you really need to replace those breakers with 20 or 25 amp breakers as a 32 amp breaker on 2.5 mm cable is dangerous, if they are protecting 4mm cable then it’s no problem.

The whole kitchen goes dark when the single kitchen breaker trips so safe to assume all 5 power outlet points and the ceiling light are fed from that one. To get by with the fryer, convection or IR oven, we usually just unplug the water heater. Admittedly, it was originally conceived as a Thai style kitchen and the only appliances were the fridge and the wall-mounted Ariston hot water heater that fed the kitchen sink mixer taps and the top loader washing machine we had at that time.

Good advice on the wire size check on those 32 A breakers, thanks. No desire to have melting wires in the roof space!

[sometimewoodworker]

I also have issues in the kitchen when the water heater is on and either the deep fat fryer or the IR oven or my convection oven are turned on at the same time. The 16 A breaker trips I assume the sparky wired all the outlets AND lights onto the same 16A service breaker. I doubt he ran heavier gauge wire to the outlets either.

The circuit should be very simple to diagnose. Just see what goes off when the breaker is off.

Also check the size of the cable coming from the breaker. And if it’s 2.5 mm you can simply replace the 16 amp breaker with a 20 or 25 amp breaker, both of those will be okay and within the specifications of the cable.

While you’ve got your consumer unit open I would also check the sizes of the cables running from the 32 amp breakers, if they are 2.5 mm cables then you really need to replace those breakers with 20 or 25 amp breakers as a 32 amp breaker on 2.5 mm cable is dangerous, if they are protecting 4mm cable then it’s no problem.

The whole kitchen goes dark when the single kitchen breaker trips so safe to assume all 5 power outlet points and the ceiling light are fed from that one. To get by with the fryer, convection or IR oven, we usually just unplug the water heater. Admittedly, it was originally conceived as a Thai style kitchen and the only appliances were the fridge and the wall-mounted Ariston hot water heater that fed the kitchen sink mixer taps and the top loader washing machine we had at that time.

Good advice on the wire size check on those 32 A breakers, thanks. No desire to have melting wires in the roof space!

One thing that you can do as a temporary fix is to run a really good extension cable (at least 2.5mm cable) from a different place in the house. You will probably have to make one up yourself as none of the commercial ones are really good enough but it’s hardly rocket science so easy enough to do.

[pf-flyer]

[quote=sometimewoodworker post_id=560648 time=1576405718 user_id=13953]
[quote=tamada post_id=560639 time=1576400016 user_id=3915]
[quote=sometimewoodworker post_id=560636 time=1576399202 user_id=13953]
[quote=tamada post_id=560627 time=1576395995 user_id=3915]

I also have issues in the kitchen when the water heater is on and either the deep fat fryer or the IR oven or my convection oven are turned on at the same time. The 16 A breaker trips I assume the sparky wired all the outlets AND lights onto the same 16A service breaker. I doubt he ran heavier gauge wire to the outlets either.

[/quote]
The circuit should be very simple to diagnose. Just see what goes off when the breaker is off.

Also check the size of the cable coming from the breaker. And if it’s 2.5 mm you can simply replace the 16 amp breaker with a 20 or 25 amp breaker, both of those will be okay and within the specifications of the cable.

While you’ve got your consumer unit open I would also check the sizes of the cables running from the 32 amp breakers, if they are 2.5 mm cables then you really need to replace those breakers with 20 or 25 amp breakers as a 32 amp breaker on 2.5 mm cable is dangerous, if they are protecting 4mm cable then it’s no problem.
[/quote]

The whole kitchen goes dark when the single kitchen breaker trips so safe to assume all 5 power outlet points and the ceiling light are fed from that one. To get by with the fryer, convection or IR oven, we usually just unplug the water heater. Admittedly, it was originally conceived as a Thai style kitchen and the only appliances were the fridge and the wall-mounted Ariston hot water heater that fed the kitchen sink mixer taps and the top loader washing machine we had at that time.

Good advice on the wire size check on those 32 A breakers, thanks. No desire to have melting wires in the roof space!
[/quote]

One thing that you can do as a temporary fix is to run a really good extension cable (at least 2.5mm cable) from a different place in the house. You will probably have to make one up yourself as none of the commercial ones are really good enough but it’s hardly rocket science so easy enough to do.
[/quote]

"Also check the size of the cable coming from the breaker. And if it’s 2.5 mm you can simply replace the 16 amp breaker with a 20 or 25 amp breaker, both of those will be okay and within the specifications of the cable."

That was the same problem that I had. Except it was a mounted water heater in the shower wired with 4mm wire and a 16 amp breaker because the was all the electrition had when we built the house. I replaced the 16 amp breaker with a 25 amp and everything works fine. I make my own extension cables. I have seen too many of the pastic ones melt. Big Lots right down the road from the Big C has everything you need to make your own

[bluejets]

Biggest downfall of all is the fact that many reside 300 metres or whatever from the supply pole and run cable not sufficiently large enough or incorrectly terminated aluminium conductors for the voltage drop which occurs over that distance at those size of loads.

[tamada]

in our new home the lights and outlets are also combined together , all our lights are led and do not consume much ,and the wiring is all 2.5sq/mm to make it easy , we have a breaker box of 18 breakers ,all 20A ,divided like this
1/ sofaroom
2/ bedroom 2
3/ bathroom 1 and 2 + grundfos waterpump
4/ ferolli hot water tank
5/ living room
6/ refrigerator
7/ bed room 1
8/ aircon 1
9/ aircon 2
10/oven + gas ignition
11/ kitchen outlets (3)
12/ kitchen outlets (2)/hood
13/ pool pump
14/ washing machines /filter home
15/ freezer
16/ kitchen counter outlets (3)
17/ terrace / carport/well pump
18/ aircon 3
as told all the lights are connected at the used room line
so each of the 18 lines can handle about 4400W, not complicated...
all outlets are grounded and protected with a RCBO/63A/ 30mA sensitivity .....
breaker box schneider
45 (Copy).JPG
as info ....

Looks great. All nice and neat. Since we're playing show and tell, here's my small disaster. It would appear that there was a sweet deal on blue wire in October 2007!

The blue wiring is marked '1 x 4 50mm' and around 4 mm o.d. so assume that is 5 mm2 solid wire rated at ~30 A. The yellow wire, same gauge, are I assume the grounds... I mean it must be as there are so few of them and they have lots of cheap black tape on connections. The skinnier red and white wires has me flummoxed for now but probably the sparky ran out of blue!

Single-breakers from left to right, the 6 x 32 A breakers are for 4 x air-conditioner outlets (but only 2 installed) and 2 x hot water shower units which each have a 32 A ELB (earth leakage breaker) mounted beside (outside) the bathroom light switches. The first of the 16 A breakers is 'all' kitchen and the remaining 5 x 16 A are for the other rooms. I will work out which is what when I have an empty house via simple elimination but already note that the master bedroom ceiling lights go off when the ensuite shower ELB is turned off!

where the gingjok live

[sometimewoodworker]

Looks great. All nice and neat. Since we're playing show and tell, here's my small disaster. It would appear that there was a sweet deal on blue wire in October 2007!

The blue wiring is marked '1 x 4 50mm' and around 4 mm o.d. so assume that is 5 mm2 solid wire rated at ~30 A. The yellow wire, same gauge, are I assume the grounds... I mean it must be as there are so few of them and they have lots of cheap black tape on connections. The skinnier red and white wires has me flummoxed for now but probably the sparky ran out of blue!

Single-breakers from left to right, the 6 x 32 A breakers are for 4 x air-conditioner outlets (but only 2 installed) and 2 x hot water shower units which each have a 32 A ELB (earth leakage breaker) mounted beside (outside) the bathroom light switches. The first of the 16 A breakers is 'all' kitchen and the remaining 5 x 16 A are for the other rooms. I will work out which is what when I have an empty house via simple elimination but already note that the master bedroom ceiling lights go off when the ensuite shower ELB is turned off!

crackerbox.jpg

5mm wire is not a standard size so that’s unlikely. The standards are 2.5, 4, 6, 10 and then the bigger ones are not usual for house wiring. If you can get a picture of the markings on one of the cables it would be helpful.

It looks as if all the wires are the same size so upgrading the kitchen breaker will be safe. To be sure (you never know until you check) I would take off the cover plate of one of the kitchen sockets to make sure the cable is still the same size as in the CU.

[AlexO]

Just be careful. Domestic wiring in Thailand can be a nightmare. As Bluejets has highlighted the distance between your point of supply and your house can have a significant effect on your system. Higher the volt drop the more current being used thus the warmer (hotter) the cables get. I had to sack the original electricians on our build as they were dangerous. Basically using bell wire with twist and tape joints for everything. We now have each room as a separate circuit wired in 2.5mm2 3 core cabling. Had to concede that one as no large loads on each circuit. Every socket in the kitchen is a separate supply so basically no tripping problems. Be careful of just increasing the size of breaker on a circuit, these are designed to trip at just over 1.5 x the rating. if you have some dodgy joints in the electrical system they can get very hot and eventually fail. (electrical fire are almost never caused by a cable failure only a connection/joint failure) and a 25A breaker will quite happily sit at 30amps or more while this happens. Rule of thumb, use a decent sized cable for each circuit. Use mechanical jointing systems ie crimp or connector strip (crocodile strip for you non Brits) for every connection. Work out where your highest load points are and add circuits rather than outlets. Keep safe.

[tamada]

Looks great. All nice and neat. Since we're playing show and tell, here's my small disaster. It would appear that there was a sweet deal on blue wire in October 2007!

The blue wiring is marked '1 x 4 50mm' and around 4 mm o.d. so assume that is 5 mm2 solid wire rated at ~30 A. The yellow wire, same gauge, are I assume the grounds... I mean it must be as there are so few of them and they have lots of cheap black tape on connections. The skinnier red and white wires has me flummoxed for now but probably the sparky ran out of blue!

Single-breakers from left to right, the 6 x 32 A breakers are for 4 x air-conditioner outlets (but only 2 installed) and 2 x hot water shower units which each have a 32 A ELB (earth leakage breaker) mounted beside (outside) the bathroom light switches. The first of the 16 A breakers is 'all' kitchen and the remaining 5 x 16 A are for the other rooms. I will work out which is what when I have an empty house via simple elimination but already note that the master bedroom ceiling lights go off when the ensuite shower ELB is turned off!

crackerbox.jpg

5mm wire is not a standard size so that’s unlikely. The standards are 2.5, 4, 6, 10 and then the bigger ones are not usual for house wiring. If you can get a picture of the markings on one of the cables it would be helpful.

It looks as if all the wires are the same size so upgrading the kitchen breaker will be safe. To be sure (you never know until you check) I would take off the cover plate of one of the kitchen sockets to make sure the cable is still the same size as in the CU.

LOL...the sparky wasn't the standard Thai electrician either. Who knows where he got all that blue wire from 12 years ago in upper Isaan?

When I said "the blue wiring is marked '1 x 4 50mm' and around 4 mm o.d." that is EXACTLY what is wrote on the insulation and that is the o.d. of the single strand wire. No additional pictures needed.

It does look like his shortcut to use heavier gauge wire for everything was handy. It's doubtful it was based on any foresight about future upgrades, extensions and greater loads though.

Good idea to check inside the outlet boxes though. I bought a house in a small village in Naklua many, many years ago that was a bargain as it was the show house and the developer had sold everything else. However, the show house power wiring had been minimal, just the sales office and the master bedroom and ensuite had been completely wired up as the logic prevailed that the property was only being viewed in daylight so they saved time and money. When they finished it off for me, the used all the off cuts and bits and bobs of wire from the other dozen or so completed villas. When I went into the roof space a year later when getting another aircon installed, there didn't appear to be any contiguous wiring runs that was more than 2 or 3 meter long. It also looked like they'd run out of insulating tape half way through the job as well! This is back in the no conduit or wire nuts days of course.

[sometimewoodworker]

LOL...the sparky wasn't the standard Thai electrician either. Who knows where he got all that blue wire from 12 years ago in upper Isaan?

When I said "the blue wiring is marked '1 x 4 50mm' and around 4 mm o.d." that is EXACTLY what is wrote on the insulation and that is the o.d. of the single strand wire. No additional pictures needed.

I would take another close look. I can virtually guarantee that the writing is actually

1 X 4 SQ MM

That is consistent with standard marking

I don’t think that any company actually makes 5mm certainly not Bangkok Cable.

If that is correct and the cable does run to the outlets then you can safely swap in a 32A breaker for the kitchen.

[kopkei]

from what i see on the picture is your main + is direct connected to the main breaker + , as should be , the main neutral seems to be connected on the grounding bar on top and than going to the main neutral breaker connection ...
i assume all yellow are the neutral cables who should be all connected at the left neutral connection bar ,but only one there ,the ones on the right side are taped together (should be at the neutral bar too, they are there?) and probably some where on the sealing also taped together ?, your main cables are 16sq/mm i think and you are lucky looks like copper cable , seems to be also the grounding cable connected (as should be ) on the top bar connector, but also with the neutral?, sometimes they will save a lot cable not bringing them to the breaker box ,but knotting them on the ceiling together...
in our home we have the 15/45A main meter and i used 25 SQ/mm copper cable to come to the house , my grounding cable is 16sq/mm all the way with 2 copper pins reaching a depth of 4M , we put them in the ground,when we dough out the septic tank... , as for colors , they have standard colors for everything , but as long as you know what color means what it is ok , i used black for neutral, red for + , blue coming from switch (+ too), green,green/yellow grounding,
the most easy would be if you need to re-wire is buy 2.5sq/mm for all , lights and outlets , not much difference in price between 1.5 and 2.5 ,using all 20A breakers , able connecting lights and outlets together , unless you have some users that need more than the 4400w/line supplied ,( this will depend how many outlets you will put and the users on this) fe heavy water heaters +4.4KW will need bigger wiring? ,our oven is 3.3kW and connected on 1 breaker with no other users..
for a normal household no need for a 100A main breaker , a 63A will do or even 32A for a small household with not many appliances connected,as we did for the pienong house ...
when using aluminum main cable you will need double size as the copper ...as info
forgot when bending cables together ,you should at least turn as far as 2 turns past insulation, so they never come off..
not like your yellow cables are done .

[tamada]

I would take another close look. I can virtually guarantee that the writing is actually

1 X 4 SQ MM

That is consistent with standard marking

I don’t think that any company actually makes 5mm certainly not Bangkok Cable.

If that is correct and the cable does run to the outlets then you can safely swap in a 32A breaker for the kitchen.

That SQ mm makes perfect sense now.

I will remove the current 16 A kitchen breaker and replace with one of the redundant aircon 32 A breakers for now.

It looks like the two aircon lines also have ELB's on them. Is this normal? I recall most (older) hotels just had a single breaker switch for in-room power isolation.

Cheers for all the tips so far.

[tamada]

from what i see on the picture is your main + is direct connected to the main breaker + , as should be , the main neutral seems to be connected on the grounding bar on top and than going to the main neutral breaker connection ...
i assume all yellow are the neutral cables who should be all connected at the left neutral connection bar ,but only one there ,the ones on the right side are taped together (should be at the neutral bar too, they are there?) and probably some where on the sealing also taped together ?, your main cables are 16sq/mm i think and you are lucky looks like copper cable , seems to be also the grounding cable connected (as should be ) on the top bar connector, but also with the neutral?, sometimes they will save a lot cable not bringing them to the breaker box ,but knotting them on the ceiling together...
in our home we have the 15/45A main meter and i used 25 SQ/mm copper cable to come to the house , my grounding cable is 16sq/mm all the way with 2 copper pins reaching a depth of 4M , we put them in the ground,when we dough out the septic tank... , as for colors , they have standard colors for everything , but as long as you know what color means what it is ok , i used black for neutral, red for + , blue coming from switch (+ too), green,green/yellow grounding,
the most easy would be if you need to re-wire is buy 2.5sq/mm for all , lights and outlets , not much difference in price between 1.5 and 2.5 ,using all 20A breakers , able connecting lights and outlets together , unless you have some users that need more than the 4400w/line supplied ,( this will depend how many outlets you will put and the users on this) fe heavy water heaters +4.4KW will need bigger wiring? ,our oven is 3.3kW and connected on 1 breaker with no other users..
for a normal household no need for a 100A main breaker , a 63A will do or even 32A for a small household with not many appliances connected,as we did for the pienong house ...
when using aluminum main cable you will need double size as the copper ...as info
forgot when bending cables together ,you should at least turn as far as 2 turns past insulation, so they never come off..
not like your yellow cables are done .

I do recall on one of my visits during construction pointing out that there weren't enough yellow conduit laid in the walls to feed all the cables to/from the CU. I guess that was down to our two room expansion from the original plans and they did squeeze in a few extra. They had already bought the 12 gang CU and thought they would get a bigger one but maybe that was as big as they could get 12 years ago without a 'special order'? Less choices back then but I do recall old Global, SCG Homemart, ToolPro and St. Mall just up the Sakon Nakhon road.

[sometimewoodworker]

That SQ mm makes perfect sense now.

I will remove the current 16 A kitchen breaker and replace with one of the redundant aircon 32 A breakers for now.

It looks like the two aircon lines also have ELB's on them. Is this normal? I recall most (older) hotels just had a single breaker switch for in-room power isolation.

Cheers for all the tips so far.

ELBs are virtually unheard of today, do you mean RCBOs/RCCBs? They are usual on showers but not normal on AC units but certainly won’t do any harm

You don’t have any in your CU and it will probably be difficult to put them on individual lines in the CU as you almost certainly will have borrowed neutrals. You an easily add them just before the showers.

If you don’t have one it would be very good practice to add one, from what you have shown so far you don’t. You should add it before the CU You probably don’t have enough room to put it in the CU.