My "hot" water heater

[JohnRoberts]

Brings new meaning to the word "hot" in hot water heater.

A couple days ago I get ready to take a shower (after making sawdust in the yard from a huge tree limb but thats a different story).

I am standing in the tub with wet feed and I stick my finger into the water stream coming from the tub faucet to adjust the temperature.. I feel the unmistakable tingle of AC voltage, and reflexively withdraw my finger. My first impulse is to dismiss the warning and stick it back in, because I have experienced false shock alarms before from my old man nerves misfiring (or maybe small actual shocks), but I look down at my wet feet standing in the cast iron tub and decide I will make a few measurements before becoming a statistic.

I located my NCVT, a cheap and over-sensitive non contact voltage tester... Sure enough it goes off like a christmas tree when I put it anywhere near my shower faucets.    No shower that night, because it could have ended very badly for me.

Yesterday in need of a hot shower, and with a sink full of dirty dishes, I disconnected the power from the faulty heater.  I finally was able to take a cold, hot shower.  8)

I have already picked up a replacement heater***, but now discovered the old plumbing is sweated into nipples on the top of the old hot water heater tank, so no way to remove it without a torch... (plumber called).

So much for my DIY self-help repair (could be worse). 

JR

*** It was fun fitting the new hot water heater into my mustang cobra... I had to un box it in the parking lot to fit it inside my car... there were guys betting I couldn't get it in (they lost). 

 

[desol]

Cast iron tub is a nice set to have. I've been thinking of scooping the one down the alley that is going to trash.

 

[emrr]

Yikes!

 

[dmp]

Shouldn't that have tripped a breaker?  Maybe you have an earthing problem too.
Maybe switch to a gas water heater...

 

[JohnRoberts]

Cast iron tub is a nice set to have. I've been thinking of scooping the one down the alley that is going to trash.

Mine is a cheap porcelain (pink  :-X ) covered tub...  Apparently enough of a ground path to feel a tingle. Clean water should not conduct much electricity.

JR

 

[JohnRoberts]

Shouldn't that have tripped a breaker?  Maybe you have an earthing problem too.
Maybe switch to a gas water heater...

Yes, you would think?    Breaker? Earthing?  I have an old school fuse box..and crappy wiring. I am not even sure where the hot water heater is fused. In my fuse box I have two double cartridge fuses above the edison base screw in fuses. My suspicion is that one double cartridge fuse is for all the fused branch circuits, and the other double cartridge is for all the in wall resistance heaters. The hot water heater drop is probably wired in with the in wall heaters. There are a half dozen or so switches in a box under the meter on the back wall of my house that haven't been touched or seen daylight for decades. It's hard to trace wires since there is a brick wall behind it, but that is my best guess. Perhaps disconnects in an outside panel so the fire department can cut power to the resistance heaters inside a burning house. 

My whole house is a poster boy for worst practices electrical wiring.....  Nothing is grounded. Historically the cold water pipes would be defacto grounded by the water main coming in under-ground, but when that steel pipe sprang a leak a couple years back i had it replaced with PVC.

The power to the heater is just a 3 wire 240V feed cable hanging down from the ceiling with the white wire cut. Black tape was wrapped around the two hot connections (no electrical box). This looks similar to the wiring for my in wall heaters that runs across my attic.)  The white wire (neutral?)  is cut flush and not connected. I am willing to bet that white wire is not connected to anything at the other end either.  :  I will probably add a new separate ground wire bond between the new water heater chassis and my fuse box, about 10' away.

I have already added DIY external ground wires to the GFCI outlet I put in my kitchen and just last weekend the GFCI outlet I put in my laundry room (for washing machine and dishwasher).  My first suspicion was that I somehow electrified the hot water plumbing but no, that was just a coincidence.

These are the only 2 grounded outlets in my entire house.  ??? (and probably still not to code).

I feel pretty lucky I did not get a serious shock.

JR

PS: I've heard reports about hot water heaters overheating and/or blowing up if a shorted heating element receives full power without thermostat control. It's odd that the 120V on the hot water pipe cleared after I disconnected only one of the two hot feeds. It seems the heat element should have provided an electrical path from the other hot (remember nothing was grounded)?

 

[PRR]

> Shouldn't that have tripped a breaker? 

HWH breaker/fuse will be 20 or 30 Amps.

"Tingle" is maybe 0.005 Amps.

JR is not juicy enough to blow a 20A fuse.

GFI/RCB is "not needed" because inside metal water pipe MUST be bonded to ground.

> the old plumbing is sweated into nipples on the top of the old hot water heater tank, so no way to remove it without a torch... (plumber called).

{DIY sigh} IAC, the old pipes won't shove-in the new heater. Cut the old tubing, and cut back another foot. Go to HD and get SharkBite push-on fittings and flex heater hoses. The heater is 3/4 female pipe-thread. Hoses can be had the same at one end, several sizes the other end. While you can get push-on end here, I would screw it. Measure your tubing. Get push-on to fit tube-stub and hose-end. I would strongly favor valves also. (What if it were a water leak instead of the electric leak? Won't flood your cellar, but flooded slab is no fun.)

Depending on energy and luck, I would want to pre-test the tank with air. Just enough comments about leaky out of the box. Half+ are jerks who can't screw-up properly, but I was sensing haphazard quality control. I aired up to 15psi in my garage, before I lugged the beast down cellar and put 300 pounds of water in it. (I happen to have the fitting, for checking gas pipe.)

There is no white-wire to a standard US water heater. It is reasonably legal to run black-white-bare cable, especially if you re-identify the white as a non-white conductor. It was silly to run black-red-white-bare cable.

Where is your BONDING between interior metal pipe and electric service? If not evident and not easily added, then ground the bare in your cable at source and to heater shell (there is a screw). Also get 2 ground straps for pipe and pick up both hot and cold water pipes.

BTW, the shock does not mean you need a new heater. Absent gross fault outside the heater (possible) then you only needed to replace the heating element. $23 not $330+. Still have to drain the tank. May have to buy a costly wrench to fit the heating element hex. May need a cheater bar, and a pal to brace the heater. And unless the heater is very new, you have other trouble queued-up, so may as well.

If you have not filled the tank yet, get the $7 brass drain valve. The plastic stoppers always drip in a few years. (I got one but failed to install it, but it is handy when.)

Some maps show earthquake areas. I think I was tricked by a promotional map. IAC, that's a big lump to fall over. There are straps to hold the tank to wall.

I further added an inch of denim/foil insulation, but a cold cellar in Maine is different from a warm slab in your area. I'll payback in 2 years, you much longer.

 

[PRR]

Cable-- US family-size water heaters can be had 3,500W or 4,500W. My small household and too-long feeder, I opted for 3,500W.

3,500W @ 240V nominal = 14.6 Amps
4,500W @ 240V nominal = 18.75 Amps

#12 Copper can take 20A short-term. But "continuous" loads must be derated 20%. A 10 or 20 gallon tank might heat so quick you could ignore this. A 30-60g tank may run for hours and should be derated.

3,500W = 14.6 Amps --> 18.25 Amp wire
4,500W = 18.75 Amps --> 23.5 Amp wire

3,500W is comfortably safe/legal on #12 cu cable.

4,500W should really be done in #10 cu cable.

In the end, I used 3,500W to avoid lamp-dim, but wired #10 and left extra height in pipes and on stand so some later owner can install a monster high-Watt heater without major re-work. (Or if I need an emergency replacement and the only thing is stock is the extra-tall model.)

There is a tank-stand. The actual application is a gas-burner heater in a garage. Someone thinks if the pilot is off the floor it won't ignite the gasoline fumes wafting off your Mustang. I used one, because I had way too much height (4' tank in 8' cellar), and to keep the tank bottom out of any flood which I should not have. Also drain-valve clearance.

There is a tank drip-pan. Clearly vital in some homes which stash the heater above a drywall ceiling. I used one mostly so I will see any leak ASAP.

You MUST have a blow-off pipe, from the top steam-valve down to within X" of the floor, so nobody gets face-scalded when the safety pops. H-D sells a cheap bit of plastic made for the job. It almost inspired me to go back for proper pipe and fitting.

Dunno your place. I need a bucket and utility pump so I can raise water up and out if I ever have to drain the tank. Maybe you can just wash the floor.

 

[dmp]

HWH breaker/fuse will be 20 or 30 Amps.
"Tingle" is maybe 0.005 Amps.
JR is not juicy enough to blow a 20A fuse.

The plumbing should be connected to earth, the plumbing should not ever be sitting at voltage. As soon as the water heater shorted it should have tripped the breaker. But as John replied, his house plumbing is isolated by a section of PVC pipe. 

Probably would be wise to run a ground wire from the pipe on either side of the PVC  so the house plumbing is earthed.  You can buy clamps that connect a wire to the pipe.

These are the only 2 grounded outlets in my entire house.  ??? (and probably still not to code).

The quick hack to add a grounded outlet in an old house is run a wire to a pipe.  If your plumbing is not earthed, how are the outlets grounded?


Do you have natural gas service? It would be big $$ savings over electric.
I installed a tankless gas water heater about 8 years ago because I wanted the space in my basement. I got more room around my table saw.

 

[JohnRoberts]

The plumbing should be connected to earth, the plumbing should not ever be sitting at voltage.

Back in the good old days with steel and even copper plumbing (my house is copper) you could count on plumbing to be a low impedance electrical conductor. Modern plumbing uses so much plastic that seems undependable now.

As soon as the water heater shorted it should have tripped the breaker.

Yes, it should have if the heater/ mains voltage fault was a low impedance path to the heater chassis, "and" the pipes were grounded to the service panel. Clearly they are not.  It seems grounding the water heater would provide that ground bond. 

But as John replied, his house plumbing is isolated by a section of PVC pipe. 

Yes, isolated from the water main running under my yard. I suspect the old galvanized steel water main provided some ground connection.

Probably would be wise to run a ground wire from the pipe on either side of the PVC  so the house plumbing is earthed.  You can buy clamps that connect a wire to the pipe.

?? the PVC run is 75' long under my yard, I don't think the towns water mains are even reliably metallic anymore. In fact I'm sure they aren't from watching them repair water main leaks around town with PVC pipe.

The quick hack to add a grounded outlet in an old house is run a wire to a pipe.  If your plumbing is not earthed, how are the outlets grounded?

My two GFCI outlets are grounded with a wire directly connected to my fuse box... I have high confidence in this ground... more than my water pipes.

Do you have natural gas service? It would be big $$ savings over electric.

sorry I though I already answered, I already purchased a new electric hot water heater and have no interest in gas.

I installed a tankless gas water heater about 8 years ago because I wanted the space in my basement. I got more room around my table saw.

I don't have a table saw either.

I plan to ground the hot water heater to my fuse box that is only a few feet away. I expect this will ground my plumbing too but I'll confirm.

JR

 

[JohnRoberts]

> Shouldn't that have tripped a breaker? 

HWH breaker/fuse will be 20 or 30 Amps.

"Tingle" is maybe 0.005 Amps.

JR is not juicy enough to blow a 20A fuse.

do not know the impedance of the voltage leak... pipes appear to be floating now.  I never found out how juicy I was,,,thankfully.

GFI/RCB is "not needed" because inside metal water pipe MUST be bonded to ground.

in any other house than mine 

> the old plumbing is sweated into nipples on the top of the old hot water heater tank, so no way to remove it without a torch... (plumber called).

{DIY sigh} IAC, the old pipes won't shove-in the new heater. Cut the old tubing, and cut back another foot. Go to HD and get SharkBite push-on fittings and flex heater hoses. The heater is 3/4 female pipe-thread. Hoses can be had the same at one end, several sizes the other end. While you can get push-on end here, I would screw it. Measure your tubing. Get push-on to fit tube-stub and hose-end. I would strongly favor valves also. (What if it were a water leak instead of the electric leak? Won't flood your cellar, but flooded slab is no fun.)

I have a local plumber showing up tomorrow morning... He is going to clean up some other legacy dubious plumbing, and leave me with screw on connection so next time is plug and play.

Depending on energy and luck, I would want to pre-test the tank with air. Just enough comments about leaky out of the box. Half+ are jerks who can't screw-up properly, but I was sensing haphazard quality control. I aired up to 15psi in my garage, before I lugged the beast down cellar and put 300 pounds of water in it. (I happen to have the fitting, for checking gas pipe.)

I am inclined to take my chances

There is no white-wire to a standard US water heater. It is reasonably legal to run black-white-bare cable, especially if you re-identify the white as a non-white conductor. It was silly to run black-red-white-bare cable.

The wire in place is red (hot), black (hot), white (clipped off), no bare AFAIK.

Where is your BONDING between interior metal pipe and electric service? If not evident and not easily added, then ground the bare in your cable at source and to heater shell (there is a screw). Also get 2 ground straps for pipe and pick up both hot and cold water pipes.

Unclear... I recall an old water faucet sticking out of my back wall, that may have a ground wire attached,,, phone ground and satellite antenna... but that old faucet may not be attached to anything.  A working faucet is a couple feet away.

I hope grounding the water heater chassis to fuse box will also ground the plumbing. We'll see. 

BTW, the shock does not mean you need a new heater. Absent gross fault outside the heater (possible) then you only needed to replace the heating element. $23 not $330+. Still have to drain the tank. May have to buy a costly wrench to fit the heating element hex. May need a cheater bar, and a pal to brace the heater. And unless the heater is very new, you have other trouble queued-up, so may as well.

Water heater is past due for replacement.  I couldn't turn off the drain valve a couple years ago and had to make my own custom size faucet washer to stop it leaking..

If you have not filled the tank yet, get the $7 brass drain valve. The plastic stoppers always drip in a few years. (I got one but failed to install it, but it is handy when.)

Tomorrow I'll get my plumber to swap it out with a proper one (I may even have a brass one laying around).

Some maps show earthquake areas. I think I was tricked by a promotional map. IAC, that's a big lump to fall over. There are straps to hold the tank to wall.

I don't expect earthquakes, maybe need a tornado or hurricane strap.  ;D

I further added an inch of denim/foil insulation, but a cold cellar in Maine is different from a warm slab in your area. I'll payback in 2 years, you much longer.

The new heater came with a surprisingly heavy roll of insulation.  I am a big believer in reducing heat loss.

JR

 

[dmp]

my fuse box has two copper grounds: one going outside, presumably to a rod driven into the ground, and one going to the main water pipe coming into the house.

 

[PRR]

> The wire in place is red (hot), black (hot), white (clipped off), no bare AFAIK.

Odd. May be very old.

If in GOOD shape, I'd consider wrapping green tape over white at both ends, and calling it the groundING conductor. But I've never looked-back after replacing old cable. (Among other things, new insulation is easier to work with.

The old assumption that water-pipes are grounds is clearly going out of style. There's obviously no point (in this situation) in tying your house to the main in the street, partly because it is dubious in this Age Of PVC, and mainly because you can't have one foot in the tub and the other in the street.

You want a handful of these:
http://www.homedepot.com/p/Blackburn-Bronze-Ground-Clamp-1-2-1-in-J-B1-25/202907605

Where copper pipe may be spliced with PVC, or metal plumbing (water heater, water meter) may be removed for service, there should be a traceable wire or known-metal pipe back to the fusebox common.

The larger question of where your whole-house ground is, is maybe more than you want to mess with. There should be one dirt-rod tested to 50(?) Ohms, or two rods un-tested. This bonded to fusebox. Town water system used to be good but is now useless. You *could* parallel your new water line with a conductor, but water co probably won't want you to tie to their main, and their main ain't what it used to be.

Living on concrete slab is a special case. Ideally you would cast a grounding terminal in with the rebar. Fabulous good dirt-ground and ensures your feet can't stray far from electric common. That doesn't happen (may not have been Approved when your house was built). Didn't even happen in my 2012 garage.

 

[PRR]

> my fuse box has two copper grounds: one going outside, presumably to a rod driven into the ground, and one going to the main water pipe coming into the house.

Knowing that much, you are far ahead of most homeowners, and sharper than many Home Inspectors I have paid.

I would not "presume" the ground rod. Even if it was installed, and never knocked-out, the clamp has tarnished. Inspect and tighten. My house ground rod was not connected, but no matter because he had shortened it when he hit rock. When I added a front room I threw 2 rods in the excavations and brought the wires inside. (Did I connect them? I should look.) Later I verified two good rods laid horizontally at the meter-pole 50' from the house. Nevertheless I added a rod at the new garage. I've "proved" rods by feeding 120V through 150W lamp and getting the ground-rise. (Low-volt meters won't work.) I seem to be averaging 130 Ohms per dirt-rod, so I'm down to 26 Ohms, in medium-damp weather. Note that a dead-short 120V to all 5 rods together would only flow <5 Amps, no fuse-blow.

I like water-pipe grounds and have been disappointed. My last, like JR's, turned out to have been replaced with PVC 6 inches outside the wall. Here it is plastic to my well, which raises more complex issues.

My "good ground" is actually the power company with pole-grounds all down the street. If I get lightning-strike, that's where the current goes. Conversely if my neighbor gets lightning-struck, I'll get a share of his hit.

 

[JohnRoberts]

> The wire in place is red (hot), black (hot), white (clipped off), no bare AFAIK.

Odd. May be very old.

Yes, fabric covered wire, same as all the in wall electric heaters, my attic is full of it... Perhaps circa 1950s, and cheapest option back then. As thick as my ring finger and seems pretty solid.

If in GOOD shape, I'd consider wrapping green tape over white at both ends, and calling it the groundING conductor. But I've never looked-back after replacing old cable. (Among other things, new insulation is easier to work with.

I seriously doubt the white is connected at the other end either.  I plan to run a separate EGC... The folks who wired my house were not big on grounds.

The old assumption that water-pipes are grounds is clearly going out of style. There's obviously no point (in this situation) in tying your house to the main in the street, partly because it is dubious in this Age Of PVC, and mainly because you can't have one foot in the tub and the other in the street.

You want a handful of these:
http://www.homedepot.com/p/Blackburn-Bronze-Ground-Clamp-1-2-1-in-J-B1-25/202907605

Where copper pipe may be spliced with PVC, or metal plumbing (water heater, water meter) may be removed for service, there should be a traceable wire or known-metal pipe back to the fusebox common.

My fuse box is literally a few feet from the hot water heater.  NO hard pvc plumbing inside my house, but some plastic flex hoses on toilet,  under sinks, etc.

The larger question of where your whole-house ground is, is maybe more than you want to mess with. There should be one dirt-rod tested to 50(?) Ohms, or two rods un-tested. This bonded to fusebox. Town water system used to be good but is now useless. You *could* parallel your new water line with a conductor, but water co probably won't want you to tie to their main, and their main ain't what it used to be.

The town water mains are probably more PVC than steel.

There is ground wire and rod(?) in the ground beneath the meter box. Opposite side of brick wall from fuse box.

Living on concrete slab is a special case. Ideally you would cast a grounding terminal in with the rebar. Fabulous good dirt-ground and ensures your feet can't stray far from electric common. That doesn't happen (may not have been Approved when your house was built). Didn't even happen in my 2012 garage.

I suspect they did the minimum (cheapest) they could get away with...  I have already replaced my water line, and sewer line, since they were not up to last for the duration. I do not expect my new 6 year water heater to last a few decades like the old one. 

I will ground bond the water heater to the fuse panel, and do not expect to have any more zippy shower moments.

JR

 

[JohnRoberts]

Sorted... 

Pex tubing between heater and house plumbing so electrically isolated.

Replaced the plastic drain valve with brass.

More later, maybe... Plumber earned his fee.

Next time will be easier, if I live that long.

JR

 

[PRR]

> fabric covered wire

Hate that stuff. Most of it, the cloth has rotted over time. My parents faced major problems... but were rescued when a developer bought the whole block for a strip mall.

> fuse box is literally a few feet from the hot water heater.

Well, there you go. Mine is much further.

> I suspect they did the minimum (cheapest) they could get away with...

Or less. There's Code, there's the Inspector, and there's stuff which isn't installed for the initial inspection and may be concealed or overlooked at final inspection. If any. And some inspectors are lax. (Some laxness can be bought but this seems to be rare in small housing, not worth it.)

> Pex tubing between heater and house plumbing so electrically isolated.

Love PEX. Flexible, easy, and you can say "no lead" to a buyer. (The globs of good old lead solder in this house's owner-installed copper were a big minus.) And as you say, vastly reduced shock when you touch plumbing.

If the dirt-rod is inspectable, inspect it. You know when a joint is dubious. If subsoil is soft, assume it is full length. Here I would assume they drove it 2 feet and sawed the excess (and he did). I was very glad to find two large rods professionally laid at the meter pole.

 

[dmp]

The globs of good old lead solder in this house's owner-installed copper were a big minus.

Always use lead free solder for plumbing!

I ran all new copper in the basement of my house and then used pex for a bathroom addition this past summer. I like copper for the family's drinking water but don't have science to back that up. Pex is probably fine.  Added bonus with pex is it will flex some in the event of a freeze and possibly not break like a metal pipe.

I would not "presume" the ground rod. Even if it was installed, and never knocked-out, the clamp has tarnished. Inspect and tighten. My house ground rod was not connected, but no matter because he had shortened it when he hit rock. When I added a front room I threw 2 rods in the excavations and brought the wires inside. (Did I connect them? I should look.) Later I verified two good rods laid horizontally at the meter-pole 50' from the house. Nevertheless I added a rod at the new garage. I've "proved" rods by feeding 120V through 150W lamp and getting the ground-rise. (Low-volt meters won't work.) I seem to be averaging 130 Ohms per dirt-rod, so I'm down to 26 Ohms, in medium-damp weather. Note that a dead-short 120V to all 5 rods together would only flow <5 Amps, no fuse-blow.

Good info, will look into this weekend.
I have a light bulb amp tester that should make this quick to try out.

 

[PRR]

> fabric covered wire

Hate that stuff. Most of it, the cloth has rotted over time. My parents faced major problems... but were rescued when a developer bought the whole block for a strip mall.

> fuse box is literally a few feet from the hot water heater.

Well, there you go. Mine is much further.

> I suspect they did the minimum (cheapest) they could get away with...

Or less. There's Code, there's the Inspector, and there's stuff which isn't installed for the initial inspection and may be concealed or overlooked at final inspection. If any. And some inspectors are lax. (Some laxness can be bought but this seems to be rare in small housing, not worth it.)

> Pex tubing between heater and house plumbing so electrically isolated.

Love PEX. Flexible, easy, and you can say "no lead" to a buyer. (The globs of good old lead solder in this house's owner-installed copper were a big minus.) And as you say, vastly reduced shock when you touch plumbing.

If the dirt-rod is inspectable, inspect it. You know when a joint is dubious. If subsoil is soft, assume it is full length. Here I would assume they drove it 2 feet and sawed the excess (and he did). I was very glad to find two large rods professionally laid at the meter pole.
_________________________

> Always use lead free solder for plumbing!

It was 1980. Glen had a plumbing kit maybe handed-down from his father. I'm quite sure this place was high-lead. If it were done right, I don't care, but it wasn't. And then re-re-modified as house layout changed. When we decided to move bathroom and kitchen around, I cut all that stuff out and sold the scrap. Got the PEX tooling and did it new. 2 foot copper at the old gas heater, and 5 feet hidden under the upstairs potty; all else is PEX.

> switch to a gas water heater...

I have high electric rates ($0.19/kwh) and I switched from gas to electric.

Special reasons. "Gas" here is only propane, no street gas. And it was an older On Demand gas water heater. This is great in that I can run hot water for 20 hours to clear a frozen sewer. OTOH in intermittent use it runs Too-Hot or straight cold. (It is older and may not be working properly.) It really would not flow a hand-wash warm stream, too close to the low end of the control valve.

Talking with our *Propane Supplier* (vested interest!), HE suggested a simple electric storage heater. Low first cost, and he said his small-household customers did not notice the running costs. (Six teenagers could be different.)

Temperature: HOT (160+) is most shower per tank gallon (mix with cold to stretch) but can be dangerous to the unwary or infirm. LukeWarm is now the suggested temp, but less storage and a possibility of germs growing in storage. I got a tempering valve to put after the heater. I used essentialy this (I did not pay that price, OR get the thermometer). This seems to be the cost-cut model with main side-fittings. There's lower-price units without the fittings you probably need. I'm running the tank above 140 and mixing to around 110 into the HW manifold.

 

[dmp]

I have heard the older on demand water heaters weren't very good.  I have a Richmond from about 6 years ago that I've been happy with.  It's precise on temp and will provide hot water when just a faucet is running to wash your hands. 
Has a digital adjustment for temp - mine is a few degrees out of calibration so a 125 F setpoint gives 118 F at the upstairs bathroom.
Never running out of hot water is a nice thing.
120 F is the suggested setpoint temp which is definitely not lukewarm???
Heating to 140 F all the time  increases your ambient waste heat - not a big deal in winter since you are heating the house anyway.