In the Shower and- Water Heater Catches Fire!

[Lancelot]

I'm enjoying a nice hot shower, then I hear a roar and see flames shooting out of the wall mounted water heater! I jump back and race for the breaker box; however, before I can flip the main breaker off, the fire goes out.

I get the building maintenance guy to have a look and he removes the old unit. It is apparent that the fire starts where three wires are fastened together with a metal clip. My guess is that the internal wiring could not handle the load, insulation melted and there was a dead short (fault) that only ended when one of the wire burned into. The 32 amp breaker protecting the water heater never tripped.

I felt nothing but scary none the less!

Be careful out there

[Forkinhades]

Can you post pictures of said unit and DB?

Sent from my GT-I9300 using Thaivisa Connect Thailand mobile app

[Crossy]

It would also be useful to know:-

The Wattage of the heater

The size of the wire feeding it

The approximate length of the cable run to the heater

Do you have an RCD either in the heater or in the distribution board?

These events can be quite spectacular, particularly if it's not a dead short and the cable is undersized for the breaker so it doesn't open rapidly.

[DavidMavec]

The newsletter links to this from "Should I visit Bali or Phuket?"

[ozyjon]

The newsletter links to this from "Should I visit Bali or Phuket?"

Either way you are going to die,, statistics prove that.

[Crossy]

The newsletter links to this from "Should I visit Bali or Phuket?"

It's a new traffic boosting feature to go with the new forum. Works well, two posters visited who wouldn't normally have bothered

OK it's a bug

[SOTIRIOS]

....and brand and age please.....

[Lancelot]

It would also be useful to know:-

The Wattage of the heater

The size of the wire feeding it

The approximate length of the cable run to the heater

Do you have an RCD either in the heater or in the distribution board?

These events can be quite spectacular, particularly if it's not a dead short and the cable is undersized for the breaker so it doesn't open rapidly.

Hi Crossy,

Wattage- 4,500 watts

Wire- I'm not familiar with metric sizes. Looked a tad under #14, American wire gauge. Three wire cable, the unit was grounded.

Length- About 25- 30 feet from the breaker box to the water heater unit.

RCD- ELSD Internal in heater

Model- Fujika, probably five years old or less.

I didn't take any pics of the old unit. The new unit is the same brand; however, I did see that there were no metal clips fastening the wire loom. The new model used a plastic ties to bunch wires into a loom.

Yeah, the short was high resistance which added to the fire works. The 32 amp breaker probably sensed it as load and therefore did not trip.

The condo wiring is concealed, the room outlets are grounded (I've never tested if the grounded pin is actually connected to ground.) Condo is around five years old.

I sure beat a hasty retreat out of the bathroom!

[Crossy]

14AWG is about 2mm² so I suspect it's 2.5mm² cable, rated at 20A it's on the line with a 4.5kW heater, to be honest, unless you take 2 hour showers it's going to be just fine.

A 10m run of 2.5mm² should easily have opened the 32A breaker it it was a dead short, so I think we're right in assuming it was a fizzer caused by a carp/corroded joint. I wonder why the internal RCD didn't open.

I would however be replacing that 32A breaker with a 20A unit just for peace of mind.

[Ulic]

I have read many similar wiring stories here on TV. So this sounds like one of the typical electrical

wiring posts. Glad to hear you escaped unscathed. A very scary and unnerving incident.

[bankruatsteve]

Just throwing out a guess here: I'm thinking that most fire related to electric are from connections that have become loose. That may not trip RCD or MCB until it becomes a true short and some times is on the neutral. Unfortunately, there is no PM for that except to make sure connections are tight when install - first time.

Good the OP didn't try to put out electric fire with water!

[Chao Lao Beach]

Even if renting, you should have a Safety Cut to cover your condo, and just take it with you if renting. Even though it may not have saved this, but it may save you !!!

Edited January 7, 2014 by Chao Lao Beach

[ripper15]

14 guage wire is rated for 15 amps. You can put a smaller breaker on a wire rated for more amperage but not a higher rated breaker on a smaller rated wire. You need to replace the breaker to fit the wire capacity to prevent a wire heating up and causing you problems.in the future as an over sized breaker will not trip until it exceeds the rated voltage differential. Scary situation and lucky the fault did not travel through the water and electrocute your butt.

As I am an American, I am not familiar with the term safety cut. Is this what we call a GFIC breaker or Ground Fault Interrupter Circuit?

Edited January 7, 2014 by ripper15

[jacko45k]

Yeah, a 32 amp breaker is a fair size, but water heaters can be 6KW plus so it might be necessary.

Very likely the wiring was under-rated... but it is sounding like a wire clamp, which should have a rubber piece to stop metal cutting into insulation, caused a hot spot.

I had a short on an extension cable which caused the insulation to melt off and the breaker, 20A, didn't pop.

Obviously the plug/socket was not fused and since the breaker fed the whole maid's quarters 20A was not excessive.

I had the outlet pipe blow off my water heater and was dancing around naked having hot water sprayed at my ankles........

ELCB wouldn't have helped in cases like this where the fault could be just Live-N.

Edited January 7, 2014 by jacko45k

[slipperylobster]

Yes..and do check the grounding wire! I would hardwire a GFI in the bathroom as well. My wife got a small shock in the shower....I opened the unit and there was a big hole in the metal component (do not know the technical term). Now I do not trust them at all. Watchout for dirty water/corrosion on the cheaper models. Some can handle that better than others. Anyways, hot showers feel good, but are bad for you. I prefer cool showers, except in December and January. On occasion, I just boil some water if its too cold. I rent, so I do not want to invest. If I owned a home, I would get some reviews online and get the best one I could afford. I even thought of putting a small shower tank on the sunny side of the house, with a small pump. I could move that when I left.

[louse1953]

It would also be useful to know:-

The Wattage of the heater

The size of the wire feeding it

The approximate length of the cable run to the heater

Do you have an RCD either in the heater or in the distribution board?

These events can be quite spectacular, particularly if it's not a dead short and the cable is undersized for the breaker so it doesn't open rapidly.

Hi Crossy,

Wattage- 4,500 watts

Wire- I'm not familiar with metric sizes. Looked a tad under #14, American wire gauge. Three wire cable, the unit was grounded.

Length- About 25- 30 feet from the breaker box to the water heater unit.

RCD- ELSD Internal in heater

Model- Fujika, probably five years old or less.

I didn't take any pics of the old unit. The new unit is the same brand; however, I did see that there were no metal clips fastening the wire loom. The new model used a plastic ties to bunch wires into a loom.

Yeah, the short was high resistance which added to the fire works. The 32 amp breaker probably sensed it as load and therefore did not trip.

The condo wiring is concealed, the room outlets are grounded (I've never tested if the grounded pin is actually connected to ground.) Condo is around five years old.

I sure beat a hasty retreat out of the bathroom!

No saftey button,no hot shower.

[louse1953]

14 guage wire is rated for 15 amps. You can put a smaller breaker on a wire rated for more amperage but not a higher rated breaker on a smaller rated wire. You need to replace the breaker to fit the wire capacity to prevent a wire heating up and causing you problems.in the future as an over sized breaker will not trip until it exceeds the rated voltage differential. Scary situation and lucky the fault did not travel through the water and electrocute your butt.

As I am an American, I am not familiar with the term safety cut. Is this what we call a GFIC breaker or Ground Fault Interrupter Circuit?

Yes.

[Lancelot]

Pics of water heater and breaker box- but they will not attach

I test the water heater ELCB often, its always worked

Edited January 8, 2014 by Lancelot

[Lancelot]

Yeah, a 32 amp breaker is a fair size, but water heaters can be 6KW plus so it might be necessary.

Very likely the wiring was under-rated... but it is sounding like a wire clamp, which should have a rubber piece to stop metal cutting into insulation, caused a hot spot.

I had a short on an extension cable which caused the insulation to melt off and the breaker, 20A, didn't pop.

Obviously the plug/socket was not fused and since the breaker fed the whole maid's quarters 20A was not excessive.

I had the outlet pipe blow off my water heater and was dancing around naked having hot water sprayed at my ankles........

ELCB wouldn't have helped in cases like this where the fault could be just Live-N.

The fire was a high resistance short where the wires were bunched together with a metal clip. The replacement unit uses a plastic tie, so at least that is an improcvement

I was thinking the same thing about the ELCB not opening in a live to neutral short circuit. As I understand ELCB, it detects leakage to ground, so if there was no leakage to ground it would not open, right? Or it could be faulty but I do test it every day and it does open the circuit immediately..

[Langsuan Man]

Scary stuff, especially if you are renting and don't have control over the "previous" installation

[Forkinhades]

Yeah, a 32 amp breaker is a fair size, but water heaters can be 6KW plus so it might be necessary.

Very likely the wiring was under-rated... but it is sounding like a wire clamp, which should have a rubber piece to stop metal cutting into insulation, caused a hot spot.

I had a short on an extension cable which caused the insulation to melt off and the breaker, 20A, didn't pop.

Obviously the plug/socket was not fused and since the breaker fed the whole maid's quarters 20A was not excessive.

I had the outlet pipe blow off my water heater and was dancing around naked having hot water sprayed at my ankles........

ELCB wouldn't have helped in cases like this where the fault could be just Live-N.

The fire was a high resistance short where the wires were bunched together with a metal clip. The replacement unit uses a plastic tie, so at least that is an improcvement

I was thinking the same thing about the ELCB not opening in a live to neutral short circuit. As I understand ELCB, it detects leakage to ground, so if there was no leakage to ground it would not open, right? Or it could be faulty but I do test it every day and it does open the circuit immediately..

Personally I don't trust the in built ELCB's, which could only be switch with no electronics inside.

Sent from my GT-I9300 using Thaivisa Connect Thailand mobile app

[thomasteve]

Yeah, a 32 amp breaker is a fair size, but water heaters can be 6KW plus so it might be necessary.

Very likely the wiring was under-rated... but it is sounding like a wire clamp, which should have a rubber piece to stop metal cutting into insulation, caused a hot spot.

I had a short on an extension cable which caused the insulation to melt off and the breaker, 20A, didn't pop.

Obviously the plug/socket was not fused and since the breaker fed the whole maid's quarters 20A was not excessive.

I had the outlet pipe blow off my water heater and was dancing around naked having hot water sprayed at my ankles........

ELCB wouldn't have helped in cases like this where the fault could be just Live-N.

The fire was a high resistance short where the wires were bunched together with a metal clip. The replacement unit uses a plastic tie, so at least that is an improcvement

I was thinking the same thing about the ELCB not opening in a live to neutral short circuit. As I understand ELCB, it detects leakage to ground, so if there was no leakage to ground it would not open, right? Or it could be faulty but I do test it every day and it does open the circuit immediately..

Personally I don't trust the in built ELCB's, which could only be switch with no electronics inside.

Sent from my GT-I9300 using Thaivisa Connect Thailand mobile app

You do wonder how they can incorporate an ELCB in a cheap shower unit when the cost of a Safe-T-Cut or similar device is already over 1000 baht.

Best advice would be to buy a more expensive model from a well known manufacturer and ideally one complying with international safety standards and marked accordingly. Beware that sometimes 'fake' or counterfeit markings may be used by some manufacturers.

I had a Stiebel Eltron model fail recently and there do seem to be some complex electronics inside including what looks like a current transformer as used in an ELCB.

[jacko45k]

Yeah, a 32 amp breaker is a fair size, but water heaters can be 6KW plus so it might be necessary.

Very likely the wiring was under-rated... but it is sounding like a wire clamp, which should have a rubber piece to stop metal cutting into insulation, caused a hot spot.

I had a short on an extension cable which caused the insulation to melt off and the breaker, 20A, didn't pop.

Obviously the plug/socket was not fused and since the breaker fed the whole maid's quarters 20A was not excessive.

I had the outlet pipe blow off my water heater and was dancing around naked having hot water sprayed at my ankles........

ELCB wouldn't have helped in cases like this where the fault could be just Live-N.

The fire was a high resistance short where the wires were bunched together with a metal clip. The replacement unit uses a plastic tie, so at least that is an improcvement

I was thinking the same thing about the ELCB not opening in a live to neutral short circuit. As I understand ELCB, it detects leakage to ground, so if there was no leakage to ground it would not open, right? Or it could be faulty but I do test it every day and it does open the circuit immediately..

An ELCB does have it's benefits as electrical shocks to people nearly always involve current to earth.

And yes, since they look for a Live-Neutral Imbalance such a high resistance short would not cause a trip, you are hoping an over-current device/component would catch that. That and the fact that in your water heater it is downstream of where a fault might occur.

Home installations in Thailand are often very poor indeed.

Edited January 8, 2014 by jacko45k

[masuk]

As I'm not getting much hot water through my electric bathroom shower, owing to very cold water coming in, just wondering what the availability of an LPG heater is in Chiang Mai.

Are they available in Thailand?

I know winter is short-lived here, but I'm rapidly tiring of tepid washes.

[jacko45k]

As I'm not getting much hot water through my electric bathroom shower, owing to very cold water coming in, just wondering what the availability of an LPG heater is in Chiang Mai.

Are they available in Thailand?

I know winter is short-lived here, but I'm rapidly tiring of tepid washes.

I upped the power rating of mine for that reason.

Another alternative is to use an immersion heater, one that stores enough hot water for a shower and keeps it hot.

Last, but not least, less water, smaller shower head!

[Crossy]

As I'm not getting much hot water through my electric bathroom shower, owing to very cold water coming in, just wondering what the availability of an LPG heater is in Chiang Mai.

Are they available in Thailand?

Yes they are available, try a search in the housing forum (one up from here) there have been a few discussions of the beasts.

[rakman]

Just throwing out a guess here: I'm thinking that most fire related to electric are from connections that have become loose. That may not trip RCD or MCB until it becomes a true short and some times is on the neutral. Unfortunately, there is no PM for that except to make sure connections are tight when install - first time.

Good the OP didn't try to put out electric fire with water!

That's my thought as well. It used to be common to find Al wiring with copper only switches and plugs. Over time, the Al would oxidize the wire increasing resistance and heat and cooling (expanding contracting the wire) which loosened the connection. While most sockets and switches are Al-Cu capable, for a while the was a problem.

In the OP's case, once the line connection comes undone under load, you get a nice plasma ball consuming the wire and anything else that will vaporize and maintain the plasma. Unless the line crosses to neutral or ground in the plasma ball, the breaker usually won't trip.

[oTwoPies]

An ELCB does have it's benefits as electrical shocks to people nearly always involve current to earth.

And yes, since they look for a Live-Neutral Imbalance.....................

Please be very careful what you advise regarding household electrics. You, in effect, are playing with peoples lives.

An ELCB DOES NOT detect a Live-Neutral imbalance as you stated:-

http://en.wikipedia.org/wiki/Earth_leakage_circuit_breaker

To detect a Live-Neutral imbalance, and protect your from an electric shock with current flow from live to earth, you need a RCCB

http://en.wikipedia.org/wiki/Residual-current_device

Further information is available in this link:-

http://electrical-engineering-portal.com/what-is-the-difference-between-mcb-mccb-elcb-and-rccb

I cannot remember who posted or when but this subject has been covered both fully and accurately in other posts on TV so I shall not repeat the info here.

Edit: Added, " with current flow from live to earth" and removed a paste

Edited January 20, 2014 by oTwoPies

[jacko45k]

An ELCB does have it's benefits as electrical shocks to people nearly always involve current to earth.

And yes, since they look for a Live-Neutral Imbalance.....................

Please be very careful what you advise regarding household electrics. You, in effect, are playing with peoples lives.

An ELCB DOES NOT detect a Live-Neutral imbalance as you stated:-

http://en.wikipedia.org/wiki/Earth_leakage_circuit_breaker

To detect a Live-Neutral imbalance, and protect your from an electric shock with current flow from live to earth, you need a RCCB

http://en.wikipedia.org/wiki/Residual-current_device

Further information is available in this link:-

http://electrical-engineering-portal.com/what-is-the-difference-between-mcb-mccb-elcb-and-rccb

I cannot remember who posted or when but this subject has been covered both fully and accurately in other posts on TV so I shall not repeat the info here.

Edit: Added, " with current flow from live to earth" and removed a paste

Quite right, but often the distinction is not made, particularly in Thailand, the place we are talking about.

Example

[Crossy]

oTwoPies is quite correct in his assertion.

However, even in the West the distinction between an RCD and an ELCB is blurred, even electricians still use the old terminology when describing an RCD.

Let's not get bogged down in the technological mire. I don't believe anyone is still making voltage-operated ELCBs for domestic use, and since the concept of earth leakage detection is very new in Thailand the chances are 99.9% that any 'ELCB' you come across will in fact be an RCD.