Replace water heater

[cheeryble]

Handyman has said the dial is not working and either v hot or cold.

IT's 4.5kw.

Probably time for a replacement.

Do you guys think the incoming cable looks like larger than 2.5mm2? Maybe 4? 

 

If wife orders a new heater from say Powerbuy or the like I'm guessing they won't fit for free as it's quite a cheap device. Any ideas of fitting price?

 

Should a new heater have any sort of extra protection like RCD or are they self protected and it will run happily like the old one has for a decade or two?

Fuse box is just a basic one with trip switches.

 

Thanks....

 

[Crossy]

The cable should be marked, it's very difficult to tell from photos.

 

Up to 4.5kW (20.5A) should be fine on 2.5mm² and a 20A breaker.

 

All modern heaters have a built in RCD/RCBO for added safety, but they all require a ground too.

[cheeryble]

1 minute ago, Crossy said:

The cable should be marked, it's very difficult to tell from photos.

 

Up to 4.5kW (20.5A) should be fine on 2.5mm² and a 20A breaker.

I knew you'd be there Crossy!

SO basically just check the breaker and swap the heater eh?

[Crossy]

A like-for-like swap should just work. But please do verify there's a ground at the heater.

[bankruatsteve]

Yeah, unless that is 3-core cable (unlikely) or ground is going out through the back wall, it appears you do not have ground.

[cheeryble]

It’s not so far to the fuse box are they normally earthed here so the cable could be changed for TW&E?

Just across boarded ceiling and thru wall

 

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[bankruatsteve]

38 minutes ago, cheeryble said:

It’s not so far to the fuse box are they normally earthed here so the cable could be changed for TW&E?

Just across boarded ceiling and thru wall

 

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First take off the cover to see what's there now - don't go poking around unless you have power off.  Assuming you don't have ground you could replace with 3-core (if you can find it sold by the meter) or just run another wire from your box.  Ty-wrap it under the current one and should look OK.  Your "fuse box" does have proper ground, yah?

[cheeryble]

Good morning to my marvellous experts.

 

Looks like it needs changing.

I didn't have time to work everything out but have a couple of useful pics inside heater and consumer unit.

First, the supply cable to the heater definitely looks above 2.5mm2 (although I understand 2.5 is adequate for 4.5kw anyway)

Second, there's no earth in the cable to heater and although I see a green wire coming out of the connector block top left inside the heater I don't see an earth coming into it from the top, so the can't be a separate earth coming from the wall.

A couple of possibilities crossed my mind.

1. THere's a pipe column just a metre or so from the heater, though whether there's anythng metal to connect an earth to .....I think the pipes are plastic.

2. The heater supply cable comes across above the ceiling a few metres from the pictured consumer unit which is on the other side of the wall. But all the wires are black or grey, so I'm thinking no earth? (Cant see the heater cable exiting the CU it must be tucked away.

What I'm wondering is whether instead of an earth using an RCBO device.

I first thought of a new RCBO consumer unit.

I then wondered if a RCBO switch unit could make all the circuits from the existing CU safe.

Either of the last two would be a bonus and a bit of an electrical upgrade.

 

Thoughts welcome.

 

[bankruatsteve]

Oh dear.  Well, you don't have earth/ground.  I don't even see an earth bar in the box.  A main RCBO would be "good" but if safety is a concern, you really need proper earth to your shower unit and the receptacles.  Again, the shower units will come with RCD protection but if something goes wrong, you really do not want to be zapped with 30ma.  Maybe that won't kill you, but likely to cause injury.  Earth/ground connection to device would prevent that.  One thing you could do with the shower is connect the ground wire from the unit to a wire that is connected to the steel in your structure - should make a good ground.

 

Is that round thing a light?  If nothing else get someone to put a crimp terminal on the wires.  The way those strands are frayed out is a good recipe for arcing (fire).

[Fruit Trader]

4 minutes ago, bankruatsteve said:

Is that round thing a light?  If nothing else get someone to put a crimp terminal on the wires.  The way those strands are frayed out is a good recipe for arcing (fire).

Its a bottle fuse.

[Fruit Trader]

45 minutes ago, cheeryble said:

 

Looks like the cable termination has been cooking.

 

[bankruatsteve]

33 minutes ago, Fruit Trader said:

Looks like the cable termination has been cooking.

Good find.  THAT is what a wire looks like that has a loose connection and arcing.  If there are scorch marks in the connector, it may well have burned it out and why your unit doesn't work any more.

 

Easy to fix if you want to give a try.  Could save you on a new unit.  But please do something for ground also.

 

ON THE OTHER HAND... I went back to your OP and don't see indication that your unit is protected with RCD (they usually label as "ELCB").  Do either of those buttons on the bottom say "TEST"?  If you don't see a button saying "TEST" it is probably not RCD protected and time for a new unit anyway.

[cheeryble]

Thanks to all!

 

I did notice the wire connection to the bottle fuse (I figured it was some kinda palaeolithic fuse!) ain't great, and also the charring of the white wire at the terminal block in the heater........the handyman had said it's the dial/rheostat thingy so maybe I was fixated on that but who knows?

 

I also notice some filled screw holes next to the heater so it's been replaced at some point.

 

The heater has been there quite a few years so I'd be kinda surprised that the white wire to the block should get looser so maybe tightening it may not be a cure.

 

Bankruatsteve i do notice from the photo in the OP the left button says RESET so presume it's protected?

In fact I just learned the right button says TEST. The two little lights to the left the bottom one says ELCB and comes on green with the power from a switch near the door. The top light POWER could come on red when the heater was initiated by water flow I believe.

The fact there;s a heater switch near the door means if it was all changed to an earth system rather than just RCBO or whatever there'd have to be some reconnecting above the ceiling or wherever that headed off to the switch. Presumably the switch doesn't need an earth its;f it would be like a light switch power in and out.

 

One thing i don't really get is why an earth is needed if one uses RCBO at the fuse box. Isn't the RCBO fully protective?

Thing is it would be great if an RCBO/s could also protect all the sockets and lights ......and presumably aircon......it would be great. But i'm guessing the cables to sockets etc are just two core like in most of Thailand so to earth them properly would essentially mean rewiring the whole place which has been running happily for a decades.

 

I guess a useful step would be for wife to ask handyman if there's a good earth within reach from the fusebox also.

 

[bankruatsteve]

OK.  Sounds like your heater does have RCD protection then.  (Did you press the TEST and then did it RESET?)  The unit's power light comes on when you on the switch?  If so, that white neutral is probably still making contact but I would check it anyway.

 

An RCD (RCBO, etc) will trip on a fault current of 30ma.  A ground wire will carry fault of any size to the ground.  In absence of a ground wire, the fault goes through YOU.  Believe me, you do not want a 30ma fault to go through you.  it will knock you on your ass and, in a slippery shower, that would also result in injury.

 

Again, a decent ground can be the steel in your structure - make sure good contact like with a screw.

 

[cheeryble]

1 hour ago, bankruatsteve said:

OK.  Sounds like your heater does have RCD protection then.  (Did you press the TEST and then did it RESET?)  The unit's power light comes on when you on the switch?  If so, that white neutral is probably still making contact but I would check it anyway.

 

An RCD (RCBO, etc) will trip on a fault current of 30ma.  A ground wire will carry fault of any size to the ground.  In absence of a ground wire, the fault goes through YOU.  Believe me, you do not want a 30ma fault to go through you.  it will knock you on your ass and, in a slippery shower, that would also result in injury.

 

Again, a decent ground can be the steel in your structure - make sure good contact like with a screw.

 

Been doing a bit of research and yes it seems to me an RCBO or RCD is specifically designed to trip before a leak is life threatening.......but certainly earth would be good in the shower heater.

I'm thinking Maybe a combo job could be done where.......if a ground can be identified close to CU or WH......the shower heater could be earthed, and the rest of the residence could be protected by RCBO at the CU alone. 

 

I also wonder if someone knows an electrician in CM fully competent at this sort of stuff......possibly a rare bird but sure there will be some. I wonder if the installation guys from Siam TV, Powerbuy etc are up to snuff and, bearing in mind they may be using subbies,would do the CU RCBOs too

 

[sometimewoodworker]

1 hour ago, cheeryble said:

Been doing a bit of research and yes it seems to me an RCBO or RCD is specifically designed to trip before a leak is life threatening..

That is very dependent on your age, Heath and trust that when you get knocked over by the kick that you don't sustain a skull or hip fracture. So a healthy person between about 10 and 60~70 is not very likely to be killed by the direct effects. But I prefer definitely not dying to maybe not dying.

 

Of course you may have a different view point. ????

[Crossy]

2 hours ago, cheeryble said:

Been doing a bit of research and yes it seems to me an RCBO or RCD is specifically designed to trip before a leak is life threatening.......but certainly earth would be good in the shower heater.

 

It's at times like this that a little knowledge is dangerous, even life threatening. The RCD/RCBO does NOT limit the shock current.

 

If your heater is earthed, even poorly (say 1000 ohms, a pretty crumby earth), then a leak from the live to the earth (220mA with our 1k earth) will indeed trip the breaker. Nobody gets even a tingle.

 

However, if your heater is not earthed any leakage is going to go through you, and it's limited only by your (wet) body resistance. It could be many times the lethal current and your life depends upon the RCD opening in <30ms. Trust me, you will know all about that (hopefully) non-lethal shock.

 

A Class-1 appliance MUST be earthed even if you have an RCD/RCBO. This earth is not negotiable!

 

Also note that the 30-30-30 (30V, 30mA, 30ms) rule is a compromise between getting nuisance trips and killing a healthy adult, the very young, old or infirm may have significantly lower tolerance.

 

Add that earth today. This means you!

 

[bankruatsteve]

Another misconception that some people have about RCD "protection" is that it will prevent getting "tingles" from <whatever>.  First of all, if you get a "tingle" it is because whatever you are touching has NO proper ground.  Secondly, a "tingle" is in the microamp range and will be ignored by RCD.

[david555]

In answer too O.P. question : " If wife orders a new heater from say Powerbuy or the like I'm guessing they won't fit for free as it's quite a cheap device. Any ideas of fitting price? "

 

When I bought a Panasonic water heather for shower from Baan & Beyond (ex Home Works Pattaya) the installation was at 800 Baht .

 

Replacement as Mazuma with many leds for RCBO and not reacting on test ,

Panasonic no led for it , but a visual mechanical dropping out pen handle to push back up after  testing. 

[KittenKong]

On 6/4/2019 at 12:01 PM, cheeryble said:

If wife orders a new heater from say Powerbuy or the like I'm guessing they won't fit for free as it's quite a cheap device. Any ideas of fitting price?

I bought a replacement water heater from Powerbuy last year. It cost 2,500B plus 400B (or maybe 500B) for installation which they came and did the next day. I also bought two new flexible hoses from Home Pro which Powerbuy changed along with the heater. I thought they did a good job.

[cheeryble]

Thnakyou all and points taken!

 

i will have the handyman explore and try to find an earth somewhere and take it from there.

 

Out of interest as well as ELCB I notice the Haier 4.5kw has a light labelled EARTH on the front on the black section.

What would this light be doing? Surely not lighting or not lighting dependent on if there's an earth connection?

[Crossy]

7 minutes ago, cheeryble said:

What would this light be doing? Surely not lighting or not lighting dependent on if there's an earth connection?

 

I bet that's what it's doing, to embarrass you into giving it an earth ????

 

Many, many years ago my dad had a Bridges power drill (before Stanley-Bridges which was before Stanley), the drill had a light which showed if you had an earth. 'Taint something new.

 

Exactly like this:-

 

[cheeryble]

 
I bet that's what it's doing, to embarrass you into giving it an earth [emoji846]
 
Many, many years ago my dad had a Bridges power drill (before Stanley-Bridges which was before Stanley), the drill had a light which showed if you had an earth. 'Taint somthing new.
 

Surprised it doesn’t say COOL/UNCOOL


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[cheeryble]

Just to round it off an earth was discovered in the CU.......white the same as all the neutrals! A new heater is now hooked up. Thanks for helpee


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[sometimewoodworker]

6 hours ago, cheeryble said:

Just to round it off an earth was discovered in the CU.......white the same as all the neutrals! A new heater is now hooked up. 

I hope the earth is no longer white.

[cheeryble]

I hope the earth is no longer white.

Think I saw some green and believe it or not run in conduit


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[bankruatsteve]

16 minutes ago, cheeryble said:

 

Think I saw some green and believe it or not run in conduit


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Just curious, how did they connect to earth?  

[cheeryble]

On June 14, 2019 at 12:41 PM, bankruatsteve said:

Just curious, how did they connect to earth?  

They retained the live and neutral as is (which also goes via a red light switch near the bathroom door) just taking a little to make fresh ends I believe, and ran white conduit from the machine up to the ceiling and followed round under the ceiling, through the wall, and connected with the earth in the CU. 

Not ideally neat......I would have preferred a TW&E new and run over the ceiling but it saved knocking holes in the ceiling and coming back to do filling a couple of times.

[bankruatsteve]

29 minutes ago, cheeryble said:

They retained the live and neutral as is (which also goes via a red light switch near the bathroom door) just taking a little to make fresh ends I believe, and ran white conduit from the machine up to the ceiling and followed round under the ceiling, through the wall, and connected with the earth in the CU. 

Not ideally neat......I would have preferred a TW&E new and run over the ceiling but it saved knocking holes in the ceiling and coming back to do filling a couple of times.

So, they ran an additional wire, perhaps green, from the shower earth to the CU, right?  Then, that wire connects to the white wire that had been identified as ground/earth and was already there?  What puzzles me is why there would already be a ground to your CU since it appears that your box does not support ground (or perhaps it does and I just can't see in the photo)?  If you want to know for sure, follow the "earth [that] was discovered" and find out where it goes - hopefully to a ground stake.  It still seems a bit suspicious to me.

[Toosetinmyways]

Was curious  to try and find the earth wire attached to the heater even knowing it was white. Can not see. You can trace the factory installed earth from pressure switch  to element to terminal block but there it ends.

Also the inlet wire clamp is undone. At the top of heater near the element it says "this appliance must be earthed.