# Using FLEX over 12?2 wire for a HWT?



## bushwickbill

I was at work today and came across something. We are wiring in the HWT tanks in this condo. As it is there is just a 12/2 wire hanging from the wall which needs to be spliced into the Connection point on the HWT. Now the the Boss wants us to just run a piece of flex Armour over the wire then put it into a 90 degree connector. And the end of the armored cable that is coming out of the wall just has no bond or anything, just has the end stuffed into the drywall? my question is this, Are we not supposed to bond both ends of the FLEX armored cable? I thought in the code book it states that both ends of amoured cable need to be Bonded as to stop possible sheath currents? 
Please can someone shed some help on this. I need to get to the bottom of this one way or another:thumbsup:
Cheers


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## MDShunk

One end is good enough. It's called "sleeving for protection", and is talked about somewhere in the code. I just forget where. Maybe Table 9, note 2.


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## Dennis Alwon

I agree if a pipe is bonded, in general, it is bonded. Why would it need to be on both ends. I could just as easily switch over to pvc as long as the metal part is not in the middle of a run-- there are a few exceptions... I am in bed without book so I will guess art.250 is where you will find this.


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## macmikeman

Might be a good idea to put a large red head on the end going into the wall and tape it with friction tape like how they ship built in ovens to prevent insulation chafing.


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## ohiosparky99

HMMM?? What about your disconnect, is the HWT within sight of the panel?


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## reddog552

*?*



ohiosparky99 said:


> HMMM?? What about your disconnect, is the HWT within sight of the panel?


 Dosent matter Code ref?


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## Rockyd

I think the OP is confusing Raceways for conductors with Enclosures for Grounding Electrode conductors.

Raceways - Only one end needs to be bonded, if in fact it isn't by the construction method. *Check out 250.118*

For a Grounding Elctrode Conductor - *check out 250.64(E)* Talks about BOTH ends if FERROUS. Lesson here is don't run your GEC in Ferrous pipe for protection. Think about running it bare, in PVC, or if it had to have hard core protection ALUMINUM IMC - *but not in a ferrous raceway, unless you plan to bond both ends!*


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## Shockdoc

Tell the boss to not be cheap and put a 1900 box on the wall with a disconnect switch and flex connector.


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## ohiosparky99

If i am reading it right, I believe 422.31 (B) says if you dont have a breaker lockout device installed permanetly, then you have to have a disconnecting means within sight, if I interpret it right?


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## crosport

The canadian code does not require a disconnect for a residential water heater.Also connecting only one end of a metallic sheath would prevent sheath currents not cause them!


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## kaboler

I don't think you have to worry about sheath currents on a 12/2. It's meant for like... big amperages. Like services or big big runs of 600A and such. Not 12/2.


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## 220/221

bushwickbill said:


> I thought in the code book it states that both ends of amoured cable need to be Bonded as to stop possible sheath currents?


 
You may be confusing this with a GEC which would need to be bonded at both ends.

I think the technical foul would be terminating the 60 degree cable at the water heater. I wouldn't lose any sleep over it because we all know NM has thwn in it.


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## 480sparky

220/221 said:


> ............. we all know NM has thwn in it.


And the proof for this is...........?


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## NolaTigaBait

480sparky said:


> And the proof for this is...........?


I think he means 90 degree conductors...


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## reddog552

ohiosparky99 said:


> If i am reading it right, I believe 422.31 (B) says if you dont have a breaker lockout device installed permanetly, then you have to have a disconnecting means within sight, if I interpret it right?


 I read that to mean U do need a lockout.I have done 100s of these and not been called on it.NOW I KNOW Thanks I guess that is one of the rules that are not well inforced?


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## 480sparky

NolaTigaBait said:


> I think he means 90 degree conductors...


Which THWN is not.


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## NolaTigaBait

reddog552 said:


> I read that to mean U do need a lockout.I have done 100s of these and not been called on it.NOW I KNOW Thanks I guess that is one of the rules that are not well inforced?


The disconnect must be within sight OR capable of being locked out.


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## NolaTigaBait

480sparky said:


> Which THWN is not.


Yeah yeah...


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## MDShunk

reddog552 said:


> I read that to mean U do need a lockout.I have done 100s of these and not been called on it.NOW I KNOW Thanks I guess that is one of the rules that are not well inforced?


You're sneaking by somehow. That disconnect for water heater thing has been going on for years and years.


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## 220/221

480sparky said:


> And the proof for this is...........?


I had to promise not to tell anyone but.....

I went to the factory and watched them make it.

Then I took some scrap pieces into the lab and had it analyzed.


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## wcord

220/221 said:


> You may be confusing this with a GEC which would need to be bonded at both ends.
> 
> I think the technical foul would be terminating the 60 degree cable at the water heater. I wouldn't lose any sleep over it because we all know NM has thwn in it.


Here in Canada our NM cable is rated 90 degrees.


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## crosport

Yeah NMD90 is rated for 90 but NMW isn't!


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## kbsparky

wcord said:


> Here in Canada our NM cable is rated 90 degrees.


Maybe so, but the EGC is undersized ...


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## RePhase277

wcord said:


> Here in Canada our NM cable is rated 90 degrees.


Our NM is rated 90 degrees as well, but we can only use it at 60 degree capacity.


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## miller_elex

Flex is used to sleeve the romex to the water heater, furnace, garbage disposal... Not the dish washer though, that's plain romex.

Don't question your boss, you haven't been doing this as long as he has. Just do what he wants and STFU.


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## Hairbone

miller_elex said:


> Don't question your boss, you haven't been doing this as long as he has. Just do what he wants and STFU.


:thumbsup:


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## bakerbrynn

sheath currents happen generally in single conductor cables. There is only one phase conductor and no others to cancel out the magnetic fields that are created. In 12/2 the magnetic field created by one conductor is 180 degrees out of phase(in single phase installation,120 degrees in 3 phase) with the other and they will cancel eachother out... no sheath currents.


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## w.krueger

#12 for a hot water tank, must be a tiny one. If its under 120 gallons it must be 125% of nameplate rating also...


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## denny3992

Why not just use carflex? ( nm flex) or smurf tube?


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## w.krueger

carflex is awesome, plus its liquid tight


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## Mshea

w.krueger said:


> #12 for a hot water tank, must be a tiny one. If its under 120 gallons it must be 125% of nameplate rating also...


Most Domestic hot water tanks have 2 3000 watt elements connected flip flop and draw 12.5 amps at 240 volts. #12 is plenty big enough for 12.5 amps.
Now connect the tank for both elements on at the same time and you need #10.

Hot water heaters do not require local disconnecting means in the Canadian code but a local circulating pump does. Pretty much has to have a motor before a local disconnect is required here. Dishwashers are another exception for residential. We only just required local disconnects for domestic furnaces. Used to be exempted in residential aqpplications.


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## w.krueger

I have a 70 gallon that has 2 4500 watt elements, I've seen many different size elements. we usually just hard wire them as long as the beaker can be locked out, which most can be now. I prefer liquidtight connectors just in case the plumbers connections fail, little extra safety never hurts. I think sleeving NM with MC is not good practice, but that's just my opinion.


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## BBQ

Almost all I have wired have a pair of 4500 watt elements.


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## w.krueger

wow BBQ, you actually agree with me on something, I think we had a breakthrew.


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## BlueearthDave

Flex the 12/2 and put a connector on the end in the sheet rock also. No disco is needed as long as you have a lockout on the breaker. Its cheeper than a disco. I wired a lot of homes this way for years. 
Wash "WAC" rules make us run 10/2 or larger for any hot water tanks. 
NMB is rated 60 deg. However the inside conductors are thwn and are 90 deg when you strip the insulation off. 
I have been wiring this way for years.


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## I_get_shocked

BlueearthDave said:


> inside conductors are thwn and are 90 deg when you strip the insulation off.
> I have been wiring this way for years.



The conductors within NM have no markings indicating insulation type/ voltage rating.

The insulated conductors within NM are NOT thwn or thhn or anything other than NM conductors, and without the sheath they are scrap.


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## Celtic

BlueearthDave said:


> NMB is rated 60 deg. However the inside conductors are thwn and are 90 deg when you strip the insulation off.
> I have been wiring this way for years.


You've been wrong for years.


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## Ewcelectric

The flex is for mech protection. Anything under 5ft needs protection. If the water tank is tall enough you can go straight in. Same thing applies on your electric furnace

Edit. The code book will tell you in meters or millimetres. But I think it's the same


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## FastFokker

Here it is:



> *12-518 Protection for cable in exposed installations (see Appendix G)*
> 
> Cable used in exposed wiring shall be adequately protected against mechanical damage where it passes through a floor, where it is less than 1.5 m above a floor, or where it is exposed to mechanical damage.





> *Rule 12-518 Protection for cable in exposed installations*
> 
> The outer jacket of non-metallic sheathed cables is not designed to adequately protected the inner insulated conductors from mechanical damage. Where exposed cables pass through floors, are located less than 1.5 m above a floor, or are exposed to potential damage, Rule 12-518 requires that they be protected from mechanical damage. This can be accomplished by such means as providing metal conduit or guard strips or by installing the cables in a location where there is no potential hazard.


Worth mentioning, you use conduit as mechanical protection for NMSC, but you can't pull NMSC through conduit as a wiring method. Probably has to do with heat dissipation.


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## sullivanth

reddog552 said:


> Dosent matter Code ref?


Art 422 - Disconnecting Means


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## Switched

Wow, this conversation has been going on for years!:whistling2:


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## xlink

Switched said:


> Wow, this conversation has been going on for years!:whistling2:


The nice thing about that is that you can now get flex without a metal core. Is it too late to replace the flex?:whistling2:


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