Implents of Electrical Destruction (IED)
- Thread starter Bacchus
- Start date
- Status
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
here is another one: This was on an ungrounded system so its actually not horribly unsafe
How so not horribly unsafe.
What is up with the green tape?
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
In an ungrounded system, the only first fault that will draw current will be line to line. In that case at least one wire in each line pair will have a working fuse.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
If it's corner grounded and that wire is on the grounded phase, a fuse in that position would be superfluous, wouldn't it?
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
Part 2 still needs an answer; what's up with the green tape?
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
The green tape was just to label the cconductors to maintain phasing. I actually did this. Fed an elevator and needed to be reworked a little so they could replace a window. I ripped the old stuff out and threw in an old switch (it was getting all redone but not yet) but didn't realize until I finished that it only had two fuses. They happened to need the elevator right then so I committed this crime to give them a few elevator cycles. I took the picture for my business cards.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Not only superfluous but a code violation I think...
John Arendt
Senior Member
- Location
- New Jersey
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
An obvious violation. The copper pipe pieces are of unequal lengths! And do not fill the clips properly, so poor contact.
fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
Left hand pipe not properly reamed. Cut or corona issue.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
In a related story in the category of "Here, hold my beer"...
This is probably an Urban Legend, but the story goes that some guy had a fuse blow in his car (probably a beat up pickup truck) and he didn't have a spare, so he replaced the fuse with a .22 cal live round. After a while the fuse got hot, with predictable results, resulting in a gunshot wound to the driver's private parts.
This is probably an Urban Legend, but the story goes that some guy had a fuse blow in his car (probably a beat up pickup truck) and he didn't have a spare, so he replaced the fuse with a .22 cal live round. After a while the fuse got hot, with predictable results, resulting in a gunshot wound to the driver's private parts.
So if it was true, the poor smuck would be a honorable mention or a Darwin Award nominee, assuming that he was no longer able to be part of the gene pool.
K8MHZ
Senior Member
- Occupation
- Electrician
Someone on a ham forum I am on said her brother did the same thing. He didn't get hurt, but the damage to the fuse block was enough to total the car.
That's why I made it.........
iceworm
Curmudgeon still using printed IEEE Color Books
- Location
- North of the 65 parallel
- Occupation
- EE (Field - as little design as possible)
That's why I made it.........
I don't know guys. Considering some of the posts on this forum - I'd say plenty live and operate is a relative way.
Not you two, of course, but others.
ice
OK
Something a bit different.
From about 20 years ago.
We were commissioning a suite of DC fed DC drives that we'd made. Some of these were quite big, 400kW, and about half were four quadrant - reversible and regenerative modes included.
The supply was from a 24-pulse rectifier producing 700Vdc and rated at about 6,000Adc. The DC bus had a couple of huge capacitor banks comprising hundreds of electrolytic capacitors.
We didn't have the facilities in our works to load test these drives at their full power rating. The current, the volts, but not both at the same time.
But a colleague and I decided that a thermal run at full chat would be a good idea. We devised a test on site. Run one drive motoring and the in regeneration. The DC bus just supplies the losses.Simple, brilliant, ingenious. We rather liked the idea.
We set it up using two DC machines that were part of Ward-Leonard system - kit that we were replacing. OK. We ran it up and left the test running for a couple of hours. All good.
Then we came to stop it. In what sequence? Well obviously stopping the motor powering the test set would remove the power input. Wouldn't it? So that's what I did.
Brain fade hardly describes what happened next. The regen drive kept regenerating into the DC link. With no power being consumed, the regen pumped up the DC link voltage. Beyond the limits of the capacitors.
Capacitors blew up like improvised explosive devices and the carnage seemed to last forever....lit up the substation walls with one blue flash after another.
The implement of electrical destruction was me. myself, and I.
Something a bit different.
From about 20 years ago.
We were commissioning a suite of DC fed DC drives that we'd made. Some of these were quite big, 400kW, and about half were four quadrant - reversible and regenerative modes included.
The supply was from a 24-pulse rectifier producing 700Vdc and rated at about 6,000Adc. The DC bus had a couple of huge capacitor banks comprising hundreds of electrolytic capacitors.
We didn't have the facilities in our works to load test these drives at their full power rating. The current, the volts, but not both at the same time.
But a colleague and I decided that a thermal run at full chat would be a good idea. We devised a test on site. Run one drive motoring and the in regeneration. The DC bus just supplies the losses.Simple, brilliant, ingenious. We rather liked the idea.
We set it up using two DC machines that were part of Ward-Leonard system - kit that we were replacing. OK. We ran it up and left the test running for a couple of hours. All good.
Then we came to stop it. In what sequence? Well obviously stopping the motor powering the test set would remove the power input. Wouldn't it? So that's what I did.
Brain fade hardly describes what happened next. The regen drive kept regenerating into the DC link. With no power being consumed, the regen pumped up the DC link voltage. Beyond the limits of the capacitors.
Capacitors blew up like improvised explosive devices and the carnage seemed to last forever....lit up the substation walls with one blue flash after another.
The implement of electrical destruction was me. myself, and I.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
The operation was a success and the patient died.
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
I've had similarly brilliant moments:slaphead:, but nothing so physically spectacular
hmy:.SceneryDriver
Senior Member
- Location
- NJ
- Occupation
- Electrical and Automation Designer
I got finished with a 480 drive panel soooopud late one night, and went to pull the temp feeder cable I had run to the main disconnect in the panel. Our shop didn't have 480v at the time, so we were using a step-up trafo. I was certain I'd killed power to the trafo... I hadn't. Like I said, it was stoooopud late.
The conductors slapped together and in a bright blue flash, all the power in the shop went out. Crappy coordination tripped the main breaker in the electrical vault, which we didn't have access to, instead of the breaker feeding the trafo. It was well past time to go home.
I was lucky the trafo was small so it limited the fault current. I also learned that it's OK to call it a day and pick up tomorrow. Working tired can get you hurt or worse. That cabinet shipped with a silver-dollar-sized deposit of copper on the inside, near the disconnect.
I too was the implement of electrical destruction on that one.
SceneryDriver
The conductors slapped together and in a bright blue flash, all the power in the shop went out. Crappy coordination tripped the main breaker in the electrical vault, which we didn't have access to, instead of the breaker feeding the trafo. It was well past time to go home.
I was lucky the trafo was small so it limited the fault current. I also learned that it's OK to call it a day and pick up tomorrow. Working tired can get you hurt or worse. That cabinet shipped with a silver-dollar-sized deposit of copper on the inside, near the disconnect.
I too was the implement of electrical destruction on that one.
SceneryDriver
Last edited:
- Status