# explain it PLEASE would be nice to hear now and then



##  (Dec 19, 2009)

How about the service panel upgrade that garnered 12 corrections?  The contractor calls to schedule an inspection so I can go over the corrections with him. I explain that I don't do that as a routine and would be happy to discuss them over the phone.

So one by one we go through the corrections and I give him the reason for each correction.  #7 was install a bonding bushing where conduit enters through an intact concentric ring.  He states that this is ridiculous and he is in fact an electrical engineer and has been for 20 years.

I told him to feel free to ignore any corrections that he deemed ridiculous and asked if he had any more questions.  Well sure he says  "#8 is bond hot and cold waters pipes to each other at the water heater, whats that for"?  I told him to apply his engineering acumen and see what he comes up with, next.  #9 install a ST22 top plate strap at over-bored top plate.  This was over his head so to speak.  He gets it now.


----------



##  (Dec 19, 2009)

Re: explain it PLEASE would be nice to hear now and then

I put this in the wrong topic ....should be res electric


----------



## JBI (Dec 21, 2009)

Re: explain it PLEASE would be nice to hear now and then

tiger - You blast the poor guy with 12 corrections AND want him to say 'please'? Somebody ought to pinch you, you're dreaming!  :lol:


----------



## jpranch (Dec 21, 2009)

Re: explain it PLEASE would be nice to hear now and then

tiger, I have seen this post and agree that it would be better under a different dicussion group. I'll try to move it. This was a great post but have to admit it is over my head. I want to move it to where it may have more exposure? I know just about enough electric to burn down my house or get killed!  :lol:  Hope this helps. jp


----------



## jpranch (Dec 21, 2009)

Re: explain it PLEASE would be nice to hear now and then

Well, after looking I think this is the best fit. Perhaps if we could get more of the NFPA croud on this site we could get a better responce?


----------



## jar546 (Dec 22, 2009)

Re: explain it PLEASE would be nice to hear now and then

Why does he have to bond the hot and cold water pipes?  Is there a shower diverter installed that would create the bond?


----------



## RJJ (Dec 22, 2009)

Re: explain it PLEASE would be nice to hear now and then

Jeff! I have the same question! ?? Why?


----------



## fatboy (Dec 22, 2009)

Re: explain it PLEASE would be nice to hear now and then

"Is there a shower diverter installed that would create the bond?"

Maybe, maybe not? Maybe it has been removed to be replaced? Where's the bonding then? We require it so that there is no question about it.


----------



## RJJ (Dec 23, 2009)

Re: explain it PLEASE would be nice to hear now and then

And if it is on a well with plastic water service?


----------



## jar546 (Dec 23, 2009)

Re: explain it PLEASE would be nice to hear now and then



			
				RJJ said:
			
		

> And if it is on a well with plastic water service?


You still have to bond the metallic water pipe when present.  The plastic water pipe cannot be used as one of the electrodes but metal stills needs to be bonded.  The only reason a jumper would be needed between hot and cold is when there is no continuity between the two.  The mixing valve provides the continuity at that point.


----------



## mtlogcabin (Dec 23, 2009)

Re: explain it PLEASE would be nice to hear now and then

I just saw this connection between the hot and cold copper lines when I was inspecting a furnance change out. The furnace guy asked me the reason for it and I replied to "bond" the water lines together then he asked

"Won't the steel water heater tank provide the continuity between the hot and cold water lines?"

I could not answer and told him to ask the state electrical inspector next time he saw him.

So for us guys who are not electrical savy what is the reason to bond the 2 line together?


----------



## smeismer (Dec 23, 2009)

Re: explain it PLEASE would be nice to hear now and then

There is typically a dielectric joint in the water heater.  Manufacturers go to some lengths to avoid corrosion, they typically install a zinc sacrificial anode in the water heater.  That having been said, the purpose of bonding the metallic lines in a house is to carry fault current to ground.


----------



## raider1 (Dec 23, 2009)

Re: explain it PLEASE would be nice to hear now and then



> the purpose of bonding the metallic lines in a house is to carry fault current to ground.


No, the purpose of bonding the water lines is to provide a path for lightning induced current to get to the earth and to provide a path for fault current to the grounded conductor and then to the source. Fault current does not seek the earth.



> The only reason a jumper would be needed between hot and cold is when there is no continuity between the two. The mixing valve provides the continuity at that point.


I agree.

Chris


----------



## raider1 (Dec 23, 2009)

Re: explain it PLEASE would be nice to hear now and then



> #7 was install a bonding bushing where conduit enters through an intact concentric ring.


Was this conduit on the line or load side of the service disconnecting means?

Chris


----------



## SBerg (Dec 29, 2009)

Re: explain it PLEASE would be nice to hear now and then

Mixing valve is not an approved bonding method.

All metal parts likely to become energized shall be bonded to the electrical grounding system. NEC 250.104 (D) (1).


----------



## raider1 (Dec 29, 2009)

Re: explain it PLEASE would be nice to hear now and then



			
				SBerg said:
			
		

> Mixing valve is not an approved bonding method.All metal parts likely to become energized shall be bonded to the electrical grounding system. NEC 250.104 (D) (1).


250.104(D)(1) is for separately derived systems which are very rare in a home.  

Second, where in the NEC does it state that a mixing valve is not an approved bonding method?

Chris


----------



## SBerg (Dec 29, 2009)

Re: explain it PLEASE would be nice to hear now and then

Ever see a UL (or other approved third party testing laboratory) sticker on a mixing valve?


----------



## raider1 (Dec 30, 2009)

Re: explain it PLEASE would be nice to hear now and then



			
				SBerg said:
			
		

> Ever see a UL (or other approved third party testing laboratory) sticker on a mixing valve?


No, never seen one on a coupling or a shut off valve either.  

So you are saying that for the water piping system to be considered bonded together it must have listed grounding and bonding components in the system?

The applicable section for bonding of metal water piping systems for a home would be 250.104(A).

250.104(A)(1).

250.104(A)(1) requires metal water piping *systems* to be bonded to the service equipment enclosure, the grounded conductor at the service equipment enclosure etc....

A metal piping system would include all the metallic components that comprise the system including a mixing valve.

There is nothing in 250.104(A)(1) that says we must jumper around a mixing valve.

Chris


----------



## peach (Dec 31, 2009)

Re: explain it PLEASE would be nice to hear now and then

raider is pretty smart.. even though he has an annoying avatar..

the shower diverter is always metal.. correct me if you've seen a plastic diverter.. everthing else may be plastic pipe, but not that.. perfect place to bond..

A bond is not a ground..

and you are not going to see a SDS in a house.. probably ever... (well.. maybe the doomsday people)...


----------



## raider1 (Dec 31, 2009)

Re: explain it PLEASE would be nice to hear now and then



			
				peach said:
			
		

> raider is pretty smart.. even though he has an annoying avatar..


If you think my avatar is annoying you might not want to meet me in person. :lol:

Chris


----------



## peach (Dec 31, 2009)

Re: explain it PLEASE would be nice to hear now and then

not what hub says.. sorry raider..

annoying is the least of my problems.. try down right aggressive.. nasty.. stone throwing ugly.. annoying is just a spur under the saddle..


----------



## dcspector (Jan 2, 2010)

Re: explain it PLEASE would be nice to hear now and then

Good reply Jeff and my motto is "when in dought Ohm it out". Hey all got meter? I use mine all the time when I question bonding / grounding continuity.


----------

