Water heaters....GFP?

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jes25

Senior Member
Location
Midwest
Some of you may have read my post in the contracting forum about changing elements in electric water heaters. All that talk about water heaters got me thinking about what would happen if the element had been bad.

I used to troubleshoot water heaters a lot when I worked in the middle east. (the plumbers would change the elements after I diagnosed the problem BTW) Anyhow there we had an European based system and a broken element would trip the RCD, which is basically GFP. So I got to thinking, wouldn't a broken element with no GFP cause some circulating current on the water and possibly cause a shock? Why doesn't the NEC require GFP (30 ma or something) for water heaters?
 
zog

zog

Senior Member
Location
Charlotte, NC
jes25 said:
Some of you may have read my post in the contracting forum about changing elements in electric water heaters. All that talk about water heaters got me thinking about what would happen if the element had been bad.

I used to troubleshoot water heaters a lot when I worked in the middle east. (the plumbers would change the elements after I diagnosed the problem BTW) Anyhow there we had an European based system and a broken element would trip the RCD, which is basically GFP. So I got to thinking, wouldn't a broken element with no GFP cause some circulating current on the water and possibly cause a shock? Why doesn't the NEC require GFP (30 ma or something) for water heaters?
Click to expand...

I think you have GFP and GFCI confused.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
zog said:
I think you have GFP and GFCI confused.
Click to expand...
Zog,
I know you work with the big stuff, but for most electricians the term "GFP" is commonly used for 30mA equipment ground fault protection as required by 427.22 and a couple of other code sections. The term GFCI is reserved for the 5mA people protection devices. The OP is suggesting that a rule like the one in 427.22 be created for electric water heaters.
 
cadpoint

cadpoint

Senior Member
Location
Durham, NC
Don,

What is a heater panel ?

In 427.22, what is a Heater panel, in respects the pipeline heaters as stated in the index - 08'?

Could this be some kind of control panel that control's the heated liquid, or even controls heat that have the liquid flowing through it, or is it just another device ?

OR would that only be as listed in the index under GFP...?
 
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PsychicViking

Member
I had a single phase 480v heating element on a dip tank burn up today where a portion of the element burnt to ground. I had 13amps on one leg and ground. I am in the process of finding a ground fault relay to prevent this from happening again. I think ground fault protection for water heaters and heat tape outside should be a requirement. I already use equipment ground fault protection(30ma) circuit breakers for heat tape.
 
don_resqcapt19

don_resqcapt19

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Staff member
Location
Illinois
Occupation
retired electrician
cadpoint said:
Don,

What is a heater panel ?

In 427.22, what is a Heater panel, in respects the pipeline heaters as stated in the index - 08'?

Could this be some kind of control panel that control's the heated liquid, or even controls heat that have the liquid flowing through it, or is it just another device ?

OR would that only be as listed in the index under GFP...?
Click to expand...
There is no "heater panel" in 427.22. Are you asking about "heating panels" in 427.23? Those are premade heaters that come in various rectangular sizes to heat things like tanks.
 
C

Crionics

Member
jes25 said:
Some of you may have read my post in the contracting forum about changing elements in electric water heaters. All that talk about water heaters got me thinking about what would happen if the element had been bad.

I used to troubleshoot water heaters a lot when I worked in the middle east. (the plumbers would change the elements after I diagnosed the problem BTW) Anyhow there we had an European based system and a broken element would trip the RCD, which is basically GFP. So I got to thinking, wouldn't a broken element with no GFP cause some circulating current on the water and possibly cause a shock? Why doesn't the NEC require GFP (30 ma or something) for water heaters?
Click to expand...

If the water system was properly grounded and bonded, why would a standard molded case breaker trip for a ground fault?
 
steve66

steve66

Senior Member
Location
Illinois
Occupation
Engineer
jes25 said:
Why doesn't the NEC require GFP (30 ma or something) for water heaters?
Click to expand...

Personally, I think that makes a lot more sense than some of the other code rules like arc fault protection.

But that is just an initial reaction or a gut feeling. I hope CMP's use a much more scientific method to determine which rules become codes.

Steve
 
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RICK NAPIER

Senior Member
Location
New Jersey
There is often problems with systems that for one reason or another are not properly grounded and bonded. I think it is an idea worth considering.
 
J

jes25

Senior Member
Location
Midwest
Crionics said:
If the water system was properly grounded and bonded, why would a standard molded case breaker trip for a ground fault?
Click to expand...

When you say 'ground fault' do you mean a fault to the tank itself, or a bad element faulting to the water?

LarryFine said:
It shouldn't, I would think, if the heater and water piping are properly bonded.
Click to expand...

I see a shock hazard even if the pipe is bonded. The water coming out of the pipe is "energized" and I think it would be at a different potential than the kitchen sink, for example.
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
jes25 said:
I see a shock hazard even if the pipe is bonded. The water coming out of the pipe is "energized" and I think it would be at a different potential than the kitchen sink, for example.
Click to expand...
Gives a new meaning to 'hot water', doesn't it? ;)
 
B

benaround

Senior Member
Location
Arizona
jes25 said:
When you say 'ground fault' do you mean a fault to the tank itself, or a bad element faulting to the water?



I see a shock hazard even if the pipe is bonded. The water coming out of the pipe is "energized" and I think it would be at a different potential than the kitchen sink, for example.
Click to expand...

jes25,

A broken element will complete a circuit to the tank and then to the EGC back to the

panel (source). This current has no reason or need to energize the water coming out of the

pipe.
 
C

Crionics

Member
jes25 said:
When you say 'ground fault' do you mean a fault to the tank itself, or a bad element faulting to the water?



I see a shock hazard even if the pipe is bonded. The water coming out of the pipe is "energized" and I think it would be at a different potential than the kitchen sink, for example.
Click to expand...

I actually had a typo, should have said wouldn't trip...The concern here seemed to be a heater element faulting out, and grounding back through the tank possibly through the water. If the electrical system was properly installed, I would imagine the breaker back at the panel would trip regardless of the element fault.
 
J

jes25

Senior Member
Location
Midwest
benaround said:
jes25,

A broken element will complete a circuit to the tank and then to the EGC back to the

panel (source). This current has no reason or need to energize the water coming out of the

pipe.
Click to expand...

I agree some current will flow through the water to the tank and back on the EGC. Saying the water is 'energized' is probably improperly worded but, you don't think some current would also flow out of the tap and through your body when your washing dishes? I think it would. I've learned on this forum that electricity takes all paths to complete a circuit.

Crionics, I'm sure you know this but the water itself won't (usually) carry enough current to trip a standard breaker, which is why I think it should be GFP.
 
cadpoint

cadpoint

Senior Member
Location
Durham, NC
Originally Posted by cadpoint
Don,

What is a heater panel ?

In 427.22, what is a Heater panel, in respects the pipeline heaters as stated in the index - 08'?

Could this be some kind of control panel that control's the heated liquid, or even controls heat that have the liquid flowing through it, or is it just another device ?

OR would that only be as listed in the index under GFP...?
Click to expand...

There is no "heater panel" in 427.22. Are you asking about "heating panels" in 427.23? Those are premade heaters that come in various rectangular sizes to heat things like tanks.
Click to expand...

If one where to go to GFP in the index ((as I did)), one of the many various available uses of a GFP it lists; pipeline heaters 427.22.

If one goes to that exact Article 427.22 heating panels is mentioned, I used the wrong suffix in my original question to you, sorry for the confusion!
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
cadpoint said:
If one where to go to GFP in the index ((as I did)), one of the many various available uses of a GFP it lists; pipeline heaters 427.22.

If one goes to that exact Article 427.22 heating panels is mentioned, I used the wrong suffix in my original question to you, sorry for the confusion!
Click to expand...
I looked past those words in 427.22.
It is my opinion that the term heating panel in that section means a product like this.
 
S

Sharpie

Senior Member
Location
PA
Can someone enlighten me? I've never had to replace a water heater element... but I thought that the elements were somehow insulated from the water. How would the current leak to the water? Also, how would the element fault to the metal tank if it fails?

Thanks for putting up with my ignorance.
 
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