Electrical Wiring Questons

[DaveS]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

[Mikey_in_NY]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

As far as I'm aware you're gonna have to run an extra wire. Sundance normally use 2 hot and a ground (no neutral), whereas I believe HS use 2 hot, ground and a neutral, but don't take my word for it - seek advice from a qualified elecetrician. If you have no strong preference between HS and Sundance you could always go for another Sundance to avoid new wiring?

[Dr. Spa]

Absolutely not.

You may be able to run an additional 1/2" conduit with just the neutral wire. Check with your local authority though.

[hot_water]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

Your safety ground must run back to the main panel, where the ground is tied to the neutral. You can't tie neutral to ground anywhere else in your circumstance, and you can't satisfy the requirement by adding a ground rod ner the spa. THat would be VERY unsafe.

Most areas will allow your safety ground to be #8 since you have #6 conductors. I haven't checked the fill calculation in the NEC, but using the calculator at www.electrician2.com/calculators/rf_calculators.html shows that your 3/4 should be ok with 4 THHN/THWN conductors. The safety ground is not treated as a current-carrying conductor for conduit fill purposes anyway. Maybe not such an easy pull, though.

If your conduit is metallic, check with your local inspector. You might be able to get away with using the conduit as the safety ground. But do check.... I've never done this, and may not be allowed in your current code. On those few cases where I've run metallic conduit, I always run the safety ground conductor anyway.

Some inspectors squawk at re-labeling a green as a white, so be sure to ask about this if your third wire is insulated in green. You inspector might make you re-pull.

Please do get a permit and get it inspected. Proper grounding is a very serious safety issue -- you can be killed. And, DO religiously check your GFI often. Those things do go bad, which is why they recommend a monthly test.

[DaveS]

Thanks for the info. The conduit is metallic, but I think I would prefer not taking the chance and run another wire to the main panel. Pulling it would be a bear, so I'll check out the calculator and see if I can run 3 #6 and a #8 through the current 3/4.

May take the advice on looking at another Sundance too.

Dave

[cheesybear]

Depends how good of grounding you'd get. The reason for the 4 wire system, is you need a GFCI somewhere in the loop now... do you currently have a GFCI somewhere?

I'm not an electrician, but my understanding is that with the method you want to do, you'd probably have too much resistance between your netural and ground, and it'd probably be tripping more often than not.

What size conduit do you have now? You only need a ground wire, and a #10 is probably sufficent. (Ground wires can be two sizes smaller than your conductors)

[cheesybear]

BTW, wiring sizes go from #6 to #8 to #10... ground wires can be 2 sizes smaller than conductors. so #10, not #8 is the smallest you can go.

[Dr. Spa]

Most areas will allow your safety ground to be #8 since you have #6 conductors.

Depending on what year NEC your local municipality has adopted, this is probably against code for pools and spas. All wires should be the same size.

If your conduit is metallic, check with your local inspector. You might be able to get away with using the conduit as the safety ground.

Though acceptable under some circumstance, not so for pools and spas.

Some inspectors squawk at re-labeling a green as a white, so be sure to ask about this if your third wire is insulated in green.

Again, acceptable under some circumstance, not so for pools and spas.

The NEC has some special and unique requirements for wiring pools and spa. Check with YOUR local municipality as they frequently adopt different year requirements, and sometime have their own odd and unique requirements.

[ps558]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

As stated you will need to check with your local code requirements. What model HS are you looking at? There breaker boxes have a 20 and 30 amp breakers in them, were you have the numbers 6 going right to your sundance spa. This means that after the HS breaker box you will need to rewire from the box to the spa. Junction boxes in spa cabinets is not a good idea either. From the HS box you will need 3 number 12's and 2 number 10's for most HS spas

Here is a link to manual look over page 28 and above in the pdf

http://www.hotspring.com/pdfs/OwnersManual_2008.pdf

If you like your sundance, why which brands

[stryker709]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

While this works in theory (connecting the hots as they were, changing the ground to a neutral, and using a ground rod (in Canada a ground electrode consists of two ground rods, not sure about the US), it is not generally an accepted method. I would wager your AHJ would never pass an installation such as this. When mixing electricity and water, don't cheap out, do it right as your life may depend on it. I always prefer a 6-3 teck90 cable (2 hots, 1 neutral and 1 ground) for any installation I do as it will work for any possible future hot tub as well. It is not only more flexible for future hot tubs, it is also quicker to install as it is rated for direct burial.

[hot_water]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

While this works in theory (connecting the hots as they were, changing the ground to a neutral, and using a ground rod (in Canada a ground electrode consists of two ground rods, not sure about the US), it is not generally an accepted method. I would wager your AHJ would never pass an installation such as this. When mixing electricity and water, don't cheap out, do it right as your life may depend on it. I always prefer a 6-3 teck90 cable (2 hots, 1 neutral and 1 ground) for any installation I do as it will work for any possible future hot tub as well. It is not only more flexible for future hot tubs, it is also quicker to install as it is rated for direct burial.

I agree with your advice, but I disagree with your statement that it works in theory. In the event of a ground fault, you must have a low-resistance path for current to flow back to to the utility company's service. Using a ground rod doesn't give you this (and isn't allowed by code). You need that copper wire running back to the main panelboard, where the ground is tied to the neutral which is tied to the center tap of the utility company's transformer. If you tie the safety ground to a ground rod (or two) you are relying on the earth as a current carrying conductor, and that's a bad gamble. You will often be able to measure voltage between ground rods... evidence that the earth isn't a very reliable conductor.

I aso think, but am not 100% sure, that you compromise the performance of the GFI if you connect the safety ground to only a ground wire. The GFI is looking for current mismatch... if the safety ground was connected to a ground rod at high resistance, you would be putting voltage on the ground rod and all things connected to that safety ground... but not necessarily providing a current path. The current path would be established when someone touched somthing connected to that safety ground. Becasue of the bonding of the system, this includes the WATER in the spa... and the user gets shocked before the GFI trips off. Not what you want.

Many people use direct burial wire. I prefer THWN (most wire sold as THHN is actually dual rated THHN/THWN) in conduit, even though it's much more painful to install. Just seems like a more bulletproof installation to me, but that's just an opinion.

[stryker709]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

While this works in theory (connecting the hots as they were, changing the ground to a neutral, and using a ground rod (in Canada a ground electrode consists of two ground rods, not sure about the US), it is not generally an accepted method. I would wager your AHJ would never pass an installation such as this. When mixing electricity and water, don't cheap out, do it right as your life may depend on it. I always prefer a 6-3 teck90 cable (2 hots, 1 neutral and 1 ground) for any installation I do as it will work for any possible future hot tub as well. It is not only more flexible for future hot tubs, it is also quicker to install as it is rated for direct burial.

I agree with your advice, but I disagree with your statement that it works in theory. In the event of a ground fault, you must have a low-resistance path for current to flow back to to the utility company's service. Using a ground rod doesn't give you this (and isn't allowed by code). You need that copper wire running back to the main panelboard, where the ground is tied to the neutral which is tied to the center tap of the utility company's transformer. If you tie the safety ground to a ground rod (or two) you are relying on the earth as a current carrying conductor, and that's a bad gamble. You will often be able to measure voltage between ground rods... evidence that the earth isn't a very reliable conductor.

Many people use direct burial wire. I prefer THWN (most wire sold as THHN is actually dual rated THHN/THWN) in conduit, even though it's much more painful to install. Just seems like a more bulletproof installation to me, but that's just an opinion.

I agree you need a continuous path back to the panel to trip a normal breaker, but not a GFCI. Since the GFCI is only looking for a 5 mA difference between the conductors and will trip in within 25 ms, it will trip as expected. As I said, an AHJ would never pass this, but it would work.

Nothing wrong with THWN in conduit, it's just that most will only pull the required two hots and a ground for spas that don't require a neutral and then the home owner gets screwed down the road, as is in this case, if he changes to a hot tub requiring a neutral.

Another advantage of your pipe method, in Canada anyways, is that we only require pvc to be trenched to 450mm instead of 600mm for cable.

Do you install an LB fitting on the side of the hot tub with your method? How do you enter the tub? Just curious as I've always used Teck. Thanks

[hot_water]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

While this works in theory (connecting the hots as they were, changing the ground to a neutral, and using a ground rod (in Canada a ground electrode consists of two ground rods, not sure about the US), it is not generally an accepted method. I would wager your AHJ would never pass an installation such as this. When mixing electricity and water, don't cheap out, do it right as your life may depend on it. I always prefer a 6-3 teck90 cable (2 hots, 1 neutral and 1 ground) for any installation I do as it will work for any possible future hot tub as well. It is not only more flexible for future hot tubs, it is also quicker to install as it is rated for direct burial.

I agree with your advice, but I disagree with your statement that it works in theory. In the event of a ground fault, you must have a low-resistance path for current to flow back to to the utility company's service. Using a ground rod doesn't give you this (and isn't allowed by code). You need that copper wire running back to the main panelboard, where the ground is tied to the neutral which is tied to the center tap of the utility company's transformer. If you tie the safety ground to a ground rod (or two) you are relying on the earth as a current carrying conductor, and that's a bad gamble. You will often be able to measure voltage between ground rods... evidence that the earth isn't a very reliable conductor.

Many people use direct burial wire. I prefer THWN (most wire sold as THHN is actually dual rated THHN/THWN) in conduit, even though it's much more painful to install. Just seems like a more bulletproof installation to me, but that's just an opinion.

I agree you need a continuous path back to the panel to trip a normal breaker, but not a GFCI. Since the GFCI is only looking for a 5 mA difference between the conductors and will trip in within 25 ms, it will trip as expected. As I said, an AHJ would never pass this, but it would work.

Nothing wrong with THWN in conduit, it's just that most will only pull the required two hots and a ground for spas that don't require a neutral and then the home owner gets screwed down the road, as is in this case, if he changes to a hot tub requiring a neutral.

Another advantage of your pipe method, in Canada anyways, is that we only require pvc to be trenched to 450mm instead of 600mm for cable.

Do you install an LB fitting on the side of the hot tub with your method? How do you enter the tub? Just curious as I've always used Teck. Thanks

I guess we can agree to disagree about the academic issue with the ground. I still contend that it will trip, but if the erth is high resistance, maybe not until a bag of salt water (person) touches something connected to that ground. Support for your argument is that you CAN add a three prong grounded outlet to an old home (really old - no bare wires) here IF the circuit is protected by a GFI. It doesn't trip until the current path is established, but you're right, it does trip quickly and saves a serious injury or death. As for a regular breaker, yes, if the overcurrent is due to a ground fault then there is no doubt whatsoever that you need that ground path back to the box. OF course, it'll trip due to regular (not ground fault) overcurrent whether there's a safety ground or not. The safety ground never carries a single electron. In any case, sounds like we agree that running the copper safety ground is the right way to do it, and it IS a hard and fast code requirement in NEC.

Yes, exactly - I use an LB, then a short length of liquidtite (we're limited to no more than 6 feet by code) inside the spa to the controller box. 3/4" sch40 PVC between the LB and the disconnect box. From disconnect to main panelboard, I like 2" conduit. Yes, that's huge overkill, but it's cheap after the pain of digging the trench (24" from the top of the conduit to grade). I run other stuff in that pipe as well, including one other other high current 240 circuit for a tankless water heater and lines for 240V outlets in the yard - so I can run an air compressor or welder in the yard. And I like to have lots of growth room. I've never used the growth room yet, but I sleep well knowing it's there and the trenching shovel doesn't have to come out of the shed again.

[stryker709]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

While this works in theory (connecting the hots as they were, changing the ground to a neutral, and using a ground rod (in Canada a ground electrode consists of two ground rods, not sure about the US), it is not generally an accepted method. I would wager your AHJ would never pass an installation such as this. When mixing electricity and water, don't cheap out, do it right as your life may depend on it. I always prefer a 6-3 teck90 cable (2 hots, 1 neutral and 1 ground) for any installation I do as it will work for any possible future hot tub as well. It is not only more flexible for future hot tubs, it is also quicker to install as it is rated for direct burial.

I agree with your advice, but I disagree with your statement that it works in theory. In the event of a ground fault, you must have a low-resistance path for current to flow back to to the utility company's service. Using a ground rod doesn't give you this (and isn't allowed by code). You need that copper wire running back to the main panelboard, where the ground is tied to the neutral which is tied to the center tap of the utility company's transformer. If you tie the safety ground to a ground rod (or two) you are relying on the earth as a current carrying conductor, and that's a bad gamble. You will often be able to measure voltage between ground rods... evidence that the earth isn't a very reliable conductor.

Many people use direct burial wire. I prefer THWN (most wire sold as THHN is actually dual rated THHN/THWN) in conduit, even though it's much more painful to install. Just seems like a more bulletproof installation to me, but that's just an opinion.

I agree you need a continuous path back to the panel to trip a normal breaker, but not a GFCI. Since the GFCI is only looking for a 5 mA difference between the conductors and will trip in within 25 ms, it will trip as expected. As I said, an AHJ would never pass this, but it would work.

Nothing wrong with THWN in conduit, it's just that most will only pull the required two hots and a ground for spas that don't require a neutral and then the home owner gets screwed down the road, as is in this case, if he changes to a hot tub requiring a neutral.

Another advantage of your pipe method, in Canada anyways, is that we only require pvc to be trenched to 450mm instead of 600mm for cable.

Do you install an LB fitting on the side of the hot tub with your method? How do you enter the tub? Just curious as I've always used Teck. Thanks

I guess we can agree to disagree about the academic issue with the ground. I still contend that it will trip, but if the erth is high resistance, maybe not until a bag of salt water (person) touches something connected to that ground. Support for your argument is that you CAN add a three prong grounded outlet to an old home (really old - no bare wires) here IF the circuit is protected by a GFI. It doesn't trip until the current path is established, but you're right, it does trip quickly and saves a serious injury or death. As for a regular breaker, yes, if the overcurrent is due to a ground fault then there is no doubt whatsoever that you need that ground path back to the box. OF course, it'll trip due to regular (not ground fault) overcurrent whether there's a safety ground or not. The safety ground never carries a single electron. In any case, sounds like we agree that running the copper safety ground is the right way to do it, and it IS a hard and fast code requirement in NEC.

Yes, exactly - I use an LB, then a short length of liquidtite (we're limited to no more than 6 feet by code) inside the spa to the controller box. 3/4" sch40 PVC between the LB and the disconnect box. From disconnect to main panelboard, I like 2" conduit. Yes, that's huge overkill, but it's cheap after the pain of digging the trench (24" from the top of the conduit to grade). I run other stuff in that pipe as well, including one other other high current 240 circuit for a tankless water heater and lines for 240V outlets in the yard - so I can run an air compressor or welder in the yard. And I like to have lots of growth room. I've never used the growth room yet, but I sleep well knowing it's there and the trenching shovel doesn't have to come out of the shed again.

The 3 prong outlets in the old home is exactly what I was thinking. After replacing the service on several old homes, GFCI breakers was always the easy way to deal with cables with no ground wire.

2" underground is overkill, but like you said, after digging a 24" trench it's pretty damn cheap compared to having to dig again, especially if someone has your power requirements in their backyard. Room for 240v outlets in the backyard is brilliant. Do they make you go deeper with direct bury cable there?

[hot_water]

I have an old Sundance spa that was originally wired with 3 #6 wires. 2 hot and a ground. All in 3/4 conduit. In looking at a new Hot Springs Spa the dealer said I need 4 wires to the Hot Springs break out box. I really don't want to have to rerun this with 1" conduit and 4 wires. Question is can I run the 3 I have now to the HS box (2 hots and a neutral) and then run a grounding wire from this box to a grounding rod and accomplish the same thing?

Thanks in Advance!

While this works in theory (connecting the hots as they were, changing the ground to a neutral, and using a ground rod (in Canada a ground electrode consists of two ground rods, not sure about the US), it is not generally an accepted method. I would wager your AHJ would never pass an installation such as this. When mixing electricity and water, don't cheap out, do it right as your life may depend on it. I always prefer a 6-3 teck90 cable (2 hots, 1 neutral and 1 ground) for any installation I do as it will work for any possible future hot tub as well. It is not only more flexible for future hot tubs, it is also quicker to install as it is rated for direct burial.

I agree with your advice, but I disagree with your statement that it works in theory. In the event of a ground fault, you must have a low-resistance path for current to flow back to to the utility company's service. Using a ground rod doesn't give you this (and isn't allowed by code). You need that copper wire running back to the main panelboard, where the ground is tied to the neutral which is tied to the center tap of the utility company's transformer. If you tie the safety ground to a ground rod (or two) you are relying on the earth as a current carrying conductor, and that's a bad gamble. You will often be able to measure voltage between ground rods... evidence that the earth isn't a very reliable conductor.

Many people use direct burial wire. I prefer THWN (most wire sold as THHN is actually dual rated THHN/THWN) in conduit, even though it's much more painful to install. Just seems like a more bulletproof installation to me, but that's just an opinion.

I agree you need a continuous path back to the panel to trip a normal breaker, but not a GFCI. Since the GFCI is only looking for a 5 mA difference between the conductors and will trip in within 25 ms, it will trip as expected. As I said, an AHJ would never pass this, but it would work.

Nothing wrong with THWN in conduit, it's just that most will only pull the required two hots and a ground for spas that don't require a neutral and then the home owner gets screwed down the road, as is in this case, if he changes to a hot tub requiring a neutral.

Another advantage of your pipe method, in Canada anyways, is that we only require pvc to be trenched to 450mm instead of 600mm for cable.

Do you install an LB fitting on the side of the hot tub with your method? How do you enter the tub? Just curious as I've always used Teck. Thanks

I guess we can agree to disagree about the academic issue with the ground. I still contend that it will trip, but if the erth is high resistance, maybe not until a bag of salt water (person) touches something connected to that ground. Support for your argument is that you CAN add a three prong grounded outlet to an old home (really old - no bare wires) here IF the circuit is protected by a GFI. It doesn't trip until the current path is established, but you're right, it does trip quickly and saves a serious injury or death. As for a regular breaker, yes, if the overcurrent is due to a ground fault then there is no doubt whatsoever that you need that ground path back to the box. OF course, it'll trip due to regular (not ground fault) overcurrent whether there's a safety ground or not. The safety ground never carries a single electron. In any case, sounds like we agree that running the copper safety ground is the right way to do it, and it IS a hard and fast code requirement in NEC.

Yes, exactly - I use an LB, then a short length of liquidtite (we're limited to no more than 6 feet by code) inside the spa to the controller box. 3/4" sch40 PVC between the LB and the disconnect box. From disconnect to main panelboard, I like 2" conduit. Yes, that's huge overkill, but it's cheap after the pain of digging the trench (24" from the top of the conduit to grade). I run other stuff in that pipe as well, including one other other high current 240 circuit for a tankless water heater and lines for 240V outlets in the yard - so I can run an air compressor or welder in the yard. And I like to have lots of growth room. I've never used the growth room yet, but I sleep well knowing it's there and the trenching shovel doesn't have to come out of the shed again.

The 3 prong outlets in the old home is exactly what I was thinking. After replacing the service on several old homes, GFCI breakers was always the easy way to deal with cables with no ground wire.

2" underground is overkill, but like you said, after digging a 24" trench it's pretty damn cheap compared to having to dig again, especially if someone has your power requirements in their backyard. Room for 240v outlets in the backyard is brilliant. Do they make you go deeper with direct bury cable there?

I don't know. I've never wanted to do direct burial, so I never paid any attention. If you pick any major US city (and often smaller ones that no one has ever heard of!), you can often find a summary of the requirements online. It might be in there... although I'm noticing with the local economic problems they aren't keeping the web page up to date like they should. I do know that they make you trench much deeper for PVC than they do for ridgid, so I imagine it would be deeper still for direct burial.

Those trenches suck. The worst is underground service entrance. They make you bury the 3" conduit very deep... either 30" to the top of the conduit or 36"... can't remember as it was a few years ago now....and wide, too, so you could put their approved fill around the conduit. And YOU gota provide the test mandrel, which costs $300 (thankfuly I have a friend that has one). But I sure do remember that it was one hell of a trench!! And I did in in August, it was 100 degrees out. Took me a week. And a lot, lot, lot of beer.

I like to put in put in a little power pole, which is a 3' tall, 2" square steel fence post with a flange at the base that I get from Home Depot for like, $15. Then I hang two NEMA 3R sub panels on it... one for the spa, and the other full of GFI breakers for the other stuff. The tankless water heater is for my outdoor hot water shower... shhhh, I heard that outdoor hot water was not approved in my area. I had all the wiring inspected then wired in the outdoor shower afterwards...my bad... now I get instant hot water, greatest thing since sliced bread, even better than the outdoor 240 outlets. It's electrically safe... and I put a backflow preventer in the line to protect the water supply. Even bought the backflow test kit, so I can test the backflow hardware myself without calling a plumber. In my area they don't require periodic tests of backflow devices for residential, so I'm actually better than legal.

PS - for anyone reading this, DO NOT try this hot water stuff at home!! I'm an idiot that thinks he knows what he's doing. Fooling with electric hot water heaters can get you, or worse, your family - killed. And there are a lot of subtle things that can go wrong that you might never think of.