ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 [2] 3   Go Down

Author Topic: A fun contest  (Read 2097 times)

Frank Koenig

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1083
Re: A fun contest
« Reply #10 on: July 15, 2020, 01:37:47 pm »

Pretty sure this lake and whatever energized it probably had a pretty good local earth ground as well.

Right. The difference is that a person can get in a lake but won't fit down a 4 or 6 in. well casing. So as long as all accessible conductive objects are bonded together and to a conductive well casing or drop pipe it will be difficult to get any large potential differences at the surface. It's not a great situation by any means. A hard line-to-ground fault is unlikely to trip overcurrent protection as we would like, and touching something with a low-resistance path back to the source-end grounding system, such as a conductive but interrupted water pipe, would be very bad under those circumstances. On the other hand, it's not so different from running line(s) and neutral without an equipment grounding conductor to an outbuilding, which NEC allowed under certain conditions until a few years ago. See 250.32 (b) (2) in the 2005 code, for example. It's good to try to think through these things -- for me at least.

--Frank
Logged
"Nature abhors a vacuum tube." -- John Pierce, Bell Labs

Stephen Swaffer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2382
Re: A fun contest
« Reply #11 on: July 15, 2020, 04:25:17 pm »

I agree-the biggest hazard here would likely be someone disconnecting a defective well pump.  Hopefully they would disconnect both hot legs-but people that use grounds for neutral sometimes wing it on other ways.  If not a conductive path back to the service could be very hazardous-incidentally, a transformer connected from a hot to ground would act just like a pump shorted hot to ground.

Yes code allowed it for a long while.  It is likely the reason it no longer allows it, is because a statistically significant number of bad things happened-statistically significant to most of us-tragic to those "statistics".

With covid, we seem to think any risk of life lost is too much-funny how electricity is approached so differently-because of familiarity?
Logged
Steve Swaffer

Peter A Viehoever

  • Newbie
  • *
  • Offline Offline
  • Posts: 9
Re: A fun contest
« Reply #12 on: July 15, 2020, 06:38:39 pm »

I’ll try to clarify and add though it has been a long time.

The well was about 100’ from the house and panel. The only use at the well was originally a 240v submersible pump. Both the buried waterline and electrical conduit were PVC. The power to the well consisted of two ‘hot’ legs and an equipment grounding conductor.

The newly added use was a 120v water treatment system. As I recall, the installer did not use the equipment grounding conductor as a bootleg neutral, at least directly. He used one leg of the 120v for the ‘hot’ and attached the equipment neutral directly to a ground rod driven at the well site. I sort of remember the new equipment ground being attached to the original equipment grounding conductor but maybe not.

I don’t believe there was any bonding between the originally supplied grounding conductor and the ground rod that was being used as a ‘neutral’. The water treatment system worked though the voltage I measured was kind of odd.

I was thinking the hazard might consist of unfortunate potentials between items of equipment, metal objects, and different spots on the ground (re: hopping away from electrical hazards with high voltages).

I didn't find a good way to tell my friends - "This is bad because...", except for it was not up to code and it was not safe but that seemed kind of vague.

Thanks
Logged

Jeff Robinson

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 79
  • Kansas City, MO
Re: A fun contest
« Reply #13 on: July 15, 2020, 11:11:41 pm »

I’ll try to clarify and add though it has been a long time.

The well was about 100’ from the house and panel. The only use at the well was originally a 240v submersible pump. Both the buried waterline and electrical conduit were PVC. The power to the well consisted of two ‘hot’ legs and an equipment grounding conductor.

The newly added use was a 120v water treatment system. As I recall, the installer did not use the equipment grounding conductor as a bootleg neutral, at least directly. He used one leg of the 120v for the ‘hot’ and attached the equipment neutral directly to a ground rod driven at the well site. I sort of remember the new equipment ground being attached to the original equipment grounding conductor but maybe not.

I don’t believe there was any bonding between the originally supplied grounding conductor and the ground rod that was being used as a ‘neutral’. The water treatment system worked though the voltage I measured was kind of odd.

I was thinking the hazard might consist of unfortunate potentials between items of equipment, metal objects, and different spots on the ground (re: hopping away from electrical hazards with high voltages).

I didn't find a good way to tell my friends - "This is bad because...", except for it was not up to code and it was not safe but that seemed kind of vague.

Thanks

How about:
"I'm the last one to touch this, and I won't leave it until it is code compliant.
Just doing my due diligence. Ma'am.
…"
Really, just mention all the toasted baptismal events with high impedance grounds electrocuting pastors, causing muscle spasms to prevent getting free of a power source that won't shut off due to the current does not reach the short circuit current level to trip the breaker quickly.
There, one run-on sentence. Extra points for explaining the inverse time trip curve.
Logged
Excerpt from Shelley's 'Ode to a Skylark':
__________________________________
Hail to thee, blithe Spirit!
Bird thou never wert
That from Heaven, or near it
Pourest thy full heart
In profuse strains of unpremeditated art
...
Such harmonious madness
From my lips would flow
The world should listen then, as I am listening now!

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16639
  • Hickory, Mississippi, USA
    • Resotune
Re: A fun contest
« Reply #14 on: July 16, 2020, 08:31:14 am »

I’ll try to clarify and add though it has been a long time.

The well was about 100’ from the house and panel. The only use at the well was originally a 240v submersible pump. Both the buried waterline and electrical conduit were PVC. The power to the well consisted of two ‘hot’ legs and an equipment grounding conductor.

The newly added use was a 120v water treatment system. As I recall, the installer did not use the equipment grounding conductor as a bootleg neutral, at least directly. He used one leg of the 120v for the ‘hot’ and attached the equipment neutral directly to a ground rod driven at the well site. I sort of remember the new equipment ground being attached to the original equipment grounding conductor but maybe not.

I don’t believe there was any bonding between the originally supplied grounding conductor and the ground rod that was being used as a ‘neutral’. The water treatment system worked though the voltage I measured was kind of odd.

I was thinking the hazard might consist of unfortunate potentials between items of equipment, metal objects, and different spots on the ground (re: hopping away from electrical hazards with high voltages).

I didn't find a good way to tell my friends - "This is bad because...", except for it was not up to code and it was not safe but that seemed kind of vague.

Thanks
Did they drive in the ground rod just for that added treatment equipment or was it already there? If already there it was probably connected to the equipment grounding conductor at some point. The EGC should be bonded to neutral at the panel.

The EGC should be sized to trip a breaker during a fault (that is the point). Not kosher but could work, trying to pick up neutral through the dirt path seems unreliable on a good day.

JR
Logged
When in doubt do what's right.

Stephen Swaffer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2382
Re: A fun contest
« Reply #15 on: July 16, 2020, 12:46:48 pm »

Did they drive in the ground rod just for that added treatment equipment or was it already there? If already there it was probably connected to the equipment grounding conductor at some point. The EGC should be bonded to neutral at the panel.

The EGC should be sized to trip a breaker during a fault (that is the point). Not kosher but could work, trying to pick up neutral through the dirt path seems unreliable on a good day.

JR

It will work until it doesn't.

Likely the water treatment was a very low power device, in which case, a stepdown transformer would likely be the lease expensive option.  You can get a 40 watt step down transformer with a built breaker for $35.  Not much cost to do the job right
Logged
Steve Swaffer

Frank DeWitt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1010
    • LBP DI Box
Re: A fun contest
« Reply #16 on: September 11, 2020, 08:30:22 pm »

How about:
Really, just mention all the toasted baptismal events with high impedance grounds electrocuting pastors, causing muscle spasms to prevent getting free of a power source that won't shut off due to the current does not reach the short circuit current level to trip the breaker quickly.
There, one run-on sentence. Extra points for explaining the inverse time trip curve.

I could only find one.  One is to many  https://www.chron.com/news/houston-texas/article/Family-settles-lawsuit-in-electrocution-death-of-1881419.php
Logged
Not to Code

Stephen Swaffer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2382
Re: A fun contest
« Reply #17 on: September 14, 2020, 04:36:02 pm »

The fix for most of those should have been GFCI breakers feeding the heaters.  This is a classic case of technology "improvements" in one field affecting another, seemingly unrelated field.  Plumbing used to be metallic-but now most baptistries are plumbed with plastic-there goes your ground path.  The last code cycle added "water" to the things that needed to be bonded in pools and similar installations.  I would think that the chlorine in pool and baptistry water would bring the conductivity up enough to trip most breakers "if" it is properly bonded.  That would allow GFCI's to be the backup safety instead of the primary safety in these cases.
Logged
Steve Swaffer

Frank DeWitt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1010
    • LBP DI Box
Re: A fun contest
« Reply #18 on: September 28, 2020, 11:00:35 am »

The fix for most of those should have been GFCI breakers feeding the heaters.  This is a classic case of technology "improvements" in one field affecting another, seemingly unrelated field.  Plumbing used to be metallic-but now most baptistries are plumbed with plastic-there goes your ground path.  The last code cycle added "water" to the things that needed to be bonded in pools and similar installations.  I would think that the chlorine in pool and baptistry water would bring the conductivity up enough to trip most breakers "if" it is properly bonded.  That would allow GFCI's to be the backup safety instead of the primary safety in these cases.

We don't use chlorine in our baptistry water as it is filled, used, and emptied in less then 24 hrs, but we do use a wireless microphone.  The heater and circulation pump are on a GFI breaker.  The heater and pump are turned off at a knife type disconnect before any one goes in the the baptistry.  (The tech crew does this and the pastor is responsible to check that it has been done.)
   
Logged
Not to Code

David Allred

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1846
Re: A fun contest
« Reply #19 on: September 28, 2020, 03:33:11 pm »

It will work until it doesn't.

Likely the water treatment was a very low power device, in which case, a stepdown transformer would likely be the lease expensive option.  You can get a 40 watt step down transformer with a built breaker for $35.  Not much cost to do the job right

Can you provide a link to one of these?  Or the proper verbage to get the correct type in a search?  I might have an application, but requiring more wattage.
Logged

ProSoundWeb Community

Re: A fun contest
« Reply #19 on: September 28, 2020, 03:33:11 pm »


Pages: 1 [2] 3   Go Up
 



Page created in 0.055 seconds with 22 queries.