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Tim Watts
Guest

Fri Jan 04, 2019 7:45 pm   



On 04/01/2019 17:31, George Herold wrote:

Quote:
You made a Jesus Cord?
OK.
I've got what I call my 'suicide' plug in my drawer. AC blades on one side,
banana jacks (at standard 3/4" separation) on other. That's much scarier
to me than the double male plug. (It gets used more often too.)


In a way, it's less bad...

Problem with Jesus Cords is - that they, out of necessity tend to plug
into accessible sockets, one in the generator, one in the nearest place
in the house.

It only takes an unsuspecting person or kid to pull that out and they
have live metal in their hands.

--
Email does not work

George Herold
Guest

Fri Jan 04, 2019 7:45 pm   



On Friday, January 4, 2019 at 1:05:22 PM UTC-5, Tim Watts wrote:
Quote:
On 04/01/2019 17:31, George Herold wrote:

You made a Jesus Cord?
OK.
I've got what I call my 'suicide' plug in my drawer. AC blades on one side,
banana jacks (at standard 3/4" separation) on other. That's much scarier
to me than the double male plug. (It gets used more often too.)

In a way, it's less bad...

Problem with Jesus Cords is - that they, out of necessity tend to plug
into accessible sockets, one in the generator, one in the nearest place
in the house.

It only takes an unsuspecting person or kid to pull that out and they
have live metal in their hands.


Sure, lots of things are possible. I'll remain more afraid of my
banana jack suicide plug.

George H.
Quote:

--
Email does not work


John Larkin
Guest

Fri Jan 04, 2019 8:45 pm   



On Fri, 4 Jan 2019 10:43:13 -0800 (PST), George Herold
<gherold_at_teachspin.com> wrote:

Quote:
On Friday, January 4, 2019 at 1:05:22 PM UTC-5, Tim Watts wrote:
On 04/01/2019 17:31, George Herold wrote:

You made a Jesus Cord?
OK.
I've got what I call my 'suicide' plug in my drawer. AC blades on one side,
banana jacks (at standard 3/4" separation) on other. That's much scarier
to me than the double male plug. (It gets used more often too.)

In a way, it's less bad...

Problem with Jesus Cords is - that they, out of necessity tend to plug
into accessible sockets, one in the generator, one in the nearest place
in the house.

It only takes an unsuspecting person or kid to pull that out and they
have live metal in their hands.

Sure, lots of things are possible. I'll remain more afraid of my
banana jack suicide plug.

George H.

--
Email does not work


A line cord with alligator clips on the end is handy. Maybe use rubber
booties on the clips.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

Steve Wilson
Guest

Fri Jan 04, 2019 9:45 pm   



George Herold <gherold_at_teachspin.com> wrote:

Quote:
I've got what I call my 'suicide' plug in my drawer. AC blades on one
side, banana jacks (at standard 3/4" separation) on other. That's much
scarier to me than the double male plug. (It gets used more often too.)


That is a widow-maker. Strictly prohibited in my shop. There are a number of
much safer alternatives.

> George H.

Steve Wilson
Guest

Fri Jan 04, 2019 9:45 pm   



George Herold <gherold_at_teachspin.com> wrote:

Quote:
On Thursday, January 3, 2019 at 7:51:04 PM UTC-5, Steve Wilson wrote:
Only if you use it.
Well the disconnect box is outside on the side of my house.
There is a pad lock on it, but the lock is old, rusty and
doesn't close anymore.
It's mainly there for looks... it sorta looks locked.

You never mentioned this earlier. If the box is locked, how can anyone
turn on the electricity while you are working on it?

It's very hard to forget that the generator is on, the new one is
quieter than the old one, but still makes a racket.

So the noise tells you electricity is available.
Huh, no it tells me the generator is on. You seemed to suggest that
I would forget it was on and then go blindly out and re-energize the AC.


No, you mentioned this earlier. If someone comes on the scene and doesn't
know you are working on the wiring, he could simply open the switch box and
turn on the power. You wouldn't necessarily know this had happened and
still consider the wires are dead. In the worst case, you would soon be
also.

Quote:
Say If I did reconnect to to local AC power line would my generator then
be trying to power the entire neighborhood? That would cause it to bog
down quickly.


Your generator is not the same frequency and phase as the AC power.

There would probably be a huge flash and the generator would be destroyed.

> George H.

In all these discussions, it appears that no one has posted the tables
showing the effects of electricity on the human body. For example, see

https://www.hydroquebec.com/safety/electric-shock/consequences-electric-
shock.html

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763825/

https://www.wikilectures.eu/w/ELECTRICITY_AND_HUMAN_BODY

https://www.allaboutcircuits.com/textbook/direct-current/chpt-
3/physiological-effects-electricity/

https://testguy.net/content/199-How-electricity-affects-your-body

https://en.wikipedia.org/wiki/Electrical_injury

https://opentextbc.ca/physicstestbook2/chapter/electric-hazards-and-the-
human-body/

https://www.tuv.com/content-media-files/usa/pdfs/1020-field-evaluation-
service-(fes)-for-u.s.-and-canada/tuv_rheinland_02
_effects_of_electrical_current_in_human_body.pdf

http://www.rad-proceedings.org/helper/download.php?
file=../papers/RadProc.2017.58.pdf

These articles generally agree that as little as 10 to 20 mA is sufficient
to prevent someone from letting go of the wires. They are frozen until
someone breaks the circuit.

George Herold
Guest

Fri Jan 04, 2019 9:45 pm   



On Friday, January 4, 2019 at 2:56:18 PM UTC-5, Steve Wilson wrote:
Quote:
George Herold <gherold_at_teachspin.com> wrote:

On Thursday, January 3, 2019 at 7:51:04 PM UTC-5, Steve Wilson wrote:
Only if you use it.
Well the disconnect box is outside on the side of my house.
There is a pad lock on it, but the lock is old, rusty and
doesn't close anymore.
It's mainly there for looks... it sorta looks locked.

You never mentioned this earlier. If the box is locked, how can anyone
turn on the electricity while you are working on it?

It's very hard to forget that the generator is on, the new one is
quieter than the old one, but still makes a racket.

So the noise tells you electricity is available.
Huh, no it tells me the generator is on. You seemed to suggest that
I would forget it was on and then go blindly out and re-energize the AC.

No, you mentioned this earlier. If someone comes on the scene and doesn't
know you are working on the wiring, he could simply open the switch box and
turn on the power. You wouldn't necessarily know this had happened and
still consider the wires are dead. In the worst case, you would soon be
also.

Steve, I'm going to stop this discussion. The possibility that my neighbor
is going to come over during a power outage, open up my connection box,
turn on the switch, and then leave without telling me.... very small.

The exposed metal of the double male plug is more of a hazard.
I'll agree with that.

George H.
Quote:

Say If I did reconnect to to local AC power line would my generator then
be trying to power the entire neighborhood? That would cause it to bog
down quickly.

Your generator is not the same frequency and phase as the AC power.

There would probably be a huge flash and the generator would be destroyed.

George H.

In all these discussions, it appears that no one has posted the tables
showing the effects of electricity on the human body. For example, see

https://www.hydroquebec.com/safety/electric-shock/consequences-electric-
shock.html

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763825/

https://www.wikilectures.eu/w/ELECTRICITY_AND_HUMAN_BODY

https://www.allaboutcircuits.com/textbook/direct-current/chpt-
3/physiological-effects-electricity/

https://testguy.net/content/199-How-electricity-affects-your-body

https://en.wikipedia.org/wiki/Electrical_injury

https://opentextbc.ca/physicstestbook2/chapter/electric-hazards-and-the-
human-body/

https://www.tuv.com/content-media-files/usa/pdfs/1020-field-evaluation-
service-(fes)-for-u.s.-and-canada/tuv_rheinland_02
_effects_of_electrical_current_in_human_body.pdf

http://www.rad-proceedings.org/helper/download.php?
file=../papers/RadProc.2017.58.pdf

These articles generally agree that as little as 10 to 20 mA is sufficient
to prevent someone from letting go of the wires. They are frozen until
someone breaks the circuit.



Guest

Fri Jan 04, 2019 11:45 pm   



On Friday, 4 January 2019 19:56:18 UTC, Steve Wilson wrote:
Quote:
George Herold <gherold_at_teachspin.com> wrote:
On Thursday, January 3, 2019 at 7:51:04 PM UTC-5, Steve Wilson wrote:


Quote:
So the noise tells you electricity is available.
Huh, no it tells me the generator is on. You seemed to suggest that
I would forget it was on and then go blindly out and re-energize the AC..

No, you mentioned this earlier. If someone comes on the scene and doesn't
know you are working on the wiring, he could simply open the switch box and
turn on the power. You wouldn't necessarily know this had happened and
still consider the wires are dead. In the worst case, you would soon be
also.

Say If I did reconnect to to local AC power line would my generator then
be trying to power the entire neighborhood? That would cause it to bog
down quickly.

Your generator is not the same frequency and phase as the AC power.

There would probably be a huge flash and the generator would be destroyed..


more likely to just trip the genny's breaker. I vaguely STR the deliberate parallelling of gens by connecting them directly together. IIRC the trick was to connect them through a lightbulb, and when the f difference was low & the bulb went out, throw the switch to lock them in sync. Can't rely on that memory though.


Quote:
In all these discussions, it appears that no one has posted the tables
showing the effects of electricity on the human body. For example, see

https://www.hydroquebec.com/safety/electric-shock/consequences-electric-
shock.html

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763825/

https://www.wikilectures.eu/w/ELECTRICITY_AND_HUMAN_BODY

https://www.allaboutcircuits.com/textbook/direct-current/chpt-
3/physiological-effects-electricity/

https://testguy.net/content/199-How-electricity-affects-your-body

https://en.wikipedia.org/wiki/Electrical_injury

https://opentextbc.ca/physicstestbook2/chapter/electric-hazards-and-the-
human-body/

https://www.tuv.com/content-media-files/usa/pdfs/1020-field-evaluation-
service-(fes)-for-u.s.-and-canada/tuv_rheinland_02
_effects_of_electrical_current_in_human_body.pdf

http://www.rad-proceedings.org/helper/download.php?
file=../papers/RadProc.2017.58.pdf

These articles generally agree that as little as 10 to 20 mA is sufficient
to prevent someone from letting go of the wires. They are frozen until
someone breaks the circuit.


For some reason articles like that tend to focus more on worst case than typical outcomes. I had numerous shocks in my teens. I made a rough estimate several years ago from the available figures that around 1 in 600 shocks is fatal.

There's a big difference between what someone skilled might do in the lab & what is sensible to leave around where children or other clueless persons might encounter it.


NT


Guest

Sat Jan 05, 2019 12:45 am   



>>https://youtu.be/qy9pltNa0rY

On Fri, 4 Jan 2019 07:48:32 -0800 (PST), edward.ming.lee_at_gmail.com
wrote:

>So, if we hang a diode on each of the 480V 3 phase. We get 240V x (1 + .75 + .75) = 576V. Right? I think their design max out at 700V. Parts get more expensive beyond 700V.

If you are using 480 V delta (with no neutral), better use ordinary 6
pulse rectifier with 6 diodes Smile.

It appears that the 700 V they were talking about was after the boost
PFC.

There are several ways of implementing a three phase PFC, one method
is to use three independent single phase rectifier+PFC. The problem is
that the DC from each unit are floating around. Mo big deal, if you
still need DC/C conferrers, just use three separate DC/DC converters
and just combine the final DC output. It appears this is what they are
doing with three holes in the PCB for DC/DC converter transformers.

If they indeed used three independent PFC modules, each starts with a
4 diode bridge, so there would be 12 diodes total. Since the AC input
to each single phase PFC module is taken between two mains phases, so
no need for a neutral connection.

John Larkin
Guest

Sat Jan 05, 2019 12:45 am   



On Fri, 4 Jan 2019 14:27:11 -0800 (PST), tabbypurr_at_gmail.com wrote:

Quote:
On Friday, 4 January 2019 19:56:18 UTC, Steve Wilson wrote:
George Herold <gherold_at_teachspin.com> wrote:
On Thursday, January 3, 2019 at 7:51:04 PM UTC-5, Steve Wilson wrote:


So the noise tells you electricity is available.
Huh, no it tells me the generator is on. You seemed to suggest that
I would forget it was on and then go blindly out and re-energize the AC.

No, you mentioned this earlier. If someone comes on the scene and doesn't
know you are working on the wiring, he could simply open the switch box and
turn on the power. You wouldn't necessarily know this had happened and
still consider the wires are dead. In the worst case, you would soon be
also.

Say If I did reconnect to to local AC power line would my generator then
be trying to power the entire neighborhood? That would cause it to bog
down quickly.

Your generator is not the same frequency and phase as the AC power.

There would probably be a huge flash and the generator would be destroyed.

more likely to just trip the genny's breaker. I vaguely STR the deliberate parallelling of gens by connecting them directly together. IIRC the trick was to connect them through a lightbulb, and when the f difference was low & the bulb went out, throw the switch to lock them in sync. Can't rely on that memory though.


I did that on ships. There is a circular instrument called a
synchroscope that rotates a pointer to show phase difference, and
light bulbs to show voltage difference. You play with a steam valve
and field until things line up, and then hit the paralleling breaker.
Once they are paralleled, you let the governors take over. It's a
little dramatic if you get it wrong.

I designed an electronic synchroscope once, a circle of LEDs and some
PLLs and stuff.

https://www.dropbox.com/s/7ooglw8uihylmb7/Synchro_Template.JPG?dl=0



--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

Clifford Heath
Guest

Sat Jan 05, 2019 12:45 am   



On 5/1/19 6:59 am, Steve Wilson wrote:
Quote:
George Herold <gherold_at_teachspin.com> wrote:

I've got what I call my 'suicide' plug in my drawer. AC blades on one
side, banana jacks (at standard 3/4" separation) on other. That's much
scarier to me than the double male plug. (It gets used more often too.)

That is a widow-maker. Strictly prohibited in my shop. There are a number of
much safer alternatives.


The entire house also has a master RCD, and each circuit has an RCD as
well. Pretty hard to kill yourself with that setup.

I have an extension lead that has an RCD breaker in the plug. I wouldn't
feel as bad about putting alligator clips on the other end of that.


Guest

Sat Jan 05, 2019 12:45 am   



On Friday, January 4, 2019 at 11:20:19 AM UTC-5, George Herold wrote:
Quote:
On Thursday, January 3, 2019 at 6:52:37 PM UTC-5, Phil Hobbs wrote:
On 1/3/19 11:43 AM, George Herold wrote:
On Wednesday, January 2, 2019 at 9:02:20 PM UTC-5, Dave Platt wrote:
In article <f601f50d-f201-44d2-8cb7-a6268090a704_at_googlegroups.com>,
George Herold <gherold_at_teachspin.com> wrote:

I haven't been following along. But when the power fails,
I switch off from the line, and then plug my generator into
my house, and use the fuse/breaker box to run different stuff...
furnace, frig, coffee maker. The frig and furnace are on different
AC lines so I've gotta plug in at different points.
I don't use any switches*, but I do have a double male three prong
plug, that's probably illegal somewhere.

As I understand it, in order for a "generator to home wiring" setup to
be legal, you need to use a real transfer switch - one which makes it
physically impossible to have both the generator, and the incoming
mains feed, hooked up to the house wiring simultaneously.

The way you're (apparently) doing it, it would be possible for you to
accidentally try to back-power the mains... if you fail to open some
of the breakers (individual-circuit or the main disconnect) or if
somebody inadvertently tries to "reset a tripped breaker" under these
conditions. A cross-connect of that sort could easily kill someone.

At the very least, if you're going to do this, I'd think it a good
idea for you to have a "lockout padlock" that you use to close the
breaker box after you open the main disconnect and the individual
circuit breakers. That would, at least, prevent some "helpful"
individual from reconnecting the line while the generator is powered
up.

Right all 'helpful' individuals are informed that there is no power,
the generator is running and not to go outside and energize the AC
cut-off switch. It only happens once every few years, and I don't
worry about it.

But people always complain when I describe what I do.

George H.


AFAIK the usual safe way to do this is what I have--an aluminum plate
with slots cut in it, bolted to the front of the panel so that the
"generator in" breaker can only be closed when the main breaker is open..

It's a cheap and very slick solution to the transfer switch problem.

We tend to lose power about once a year, usually for less than a day.
Late last winter we were out for 8 days. I got on the Con Edison outage
page, and by extrapolating their progress during Day 1, I figured it
would be about that long. There were no generators to be had by then,
so I got one online, and had the electricians in to do the transfer
switch and feed cable. (The generator goes outside, chained to a large
Metasequoia.) I was up and running by Day 4, total cost $400 for a 4.4
kW generator and $1k for the electricians.

Right, I'm a cheapskate and wanted to avoid the ~$1k for transfer
switch and electrician. Well the first time I did this I wasn't thinking
about safety, just getting the furnace running to stay warm.


That thing he's talking about is an interlock kit for which you will be ripped off over $100. If your generator is powering a minimal load: furnace, refrigeration, essential lighting, some kitchen receptacles for small appliances and whatever else you can fit onto a 30A feed safely, then you use a MUCH cheaper 30 Amp transfer switch powering a subpanel containing your critical circuits. The transfer switch receives power through 30 Amp dual 240V breaker in your main panel and the generator. Obviously you want this installed near your main panel to simply moving the circuit cables around, you can splice wires with wire nuts that remain in the main panel enclosure to give you some reach if necessary on the circuits that need moving from main to sub panel. And, if you match manufacturers, you can reuse the CBs from the main panel in the subpanel, which will be a big savings. And things remain cheap if you use all indoor rated components. If your generator is outside, then you install an outdoor receptacle, your only outdoor rated part, to receive its plug, and run a 6ga from the receptacle to your interior transfer switch. You end up with a code compliant, perfectly safe and convenient setup, so no headaches if you ever need the house inspected for some reason.

Quote:

George H.

(Side note: after making my own double male three pronged plug I found
that the previous owner had made one too. (found in the back of a drawer
with other electronics bits.) I've always figured he did the same trick.)



Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com



Guest

Sat Jan 05, 2019 1:45 am   



On Friday, 4 January 2019 23:16:56 UTC, Clifford Heath wrote:
Quote:
On 5/1/19 6:59 am, Steve Wilson wrote:
George Herold <gherold_at_teachspin.com> wrote:

I've got what I call my 'suicide' plug in my drawer. AC blades on one
side, banana jacks (at standard 3/4" separation) on other. That's much
scarier to me than the double male plug. (It gets used more often too.)

That is a widow-maker. Strictly prohibited in my shop. There are a number of
much safer alternatives.

The entire house also has a master RCD, and each circuit has an RCD as
well. Pretty hard to kill yourself with that setup.

I have an extension lead that has an RCD breaker in the plug. I wouldn't
feel as bad about putting alligator clips on the other end of that.


RCDs certainly don't stop all shocks, but they help a fair bit.


NT


Guest

Sat Jan 05, 2019 2:45 am   



Quote:
So, if we hang a diode on each of the 480V 3 phase. We get
240V x (1 + .75 + .75) = 576V. Right? I think their design max out at 700V.
Parts get more expensive beyond 700V.

If you are using 480 V delta (with no neutral), better use ordinary 6
pulse rectifier with 6 diodes Smile.

It appears that the 700 V they were talking about was after the boost
PFC.


Quote:
There are several ways of implementing a three phase PFC, one method
is to use three independent single phase rectifier+PFC. The problem is
that the DC from each unit are floating around. Mo big deal, if you
still need DC/C conferrers, just use three separate DC/DC converters
and just combine the final DC output. It appears this is what they are
doing with three holes in the PCB for DC/DC converter transformers.


The more I read about 3-phase power, the less I understand. But anyway,
I'll just make use of other people's work. One suggestion is using
18 pulses phase shifting transformer instead of active PFC circuit.
Disadvantage is the weight and size. Advantage is the simplicity
and less semiconductor to go bad.

Steve Wilson
Guest

Sat Jan 05, 2019 4:45 am   



George Herold <gherold_at_teachspin.com> wrote:

Quote:
Steve, I'm going to stop this discussion. The possibility that my
neighbor is going to come over during a power outage, open up my
connection box, turn on the switch, and then leave without telling
me.... very small.


Sorry, I misinterpreted your earlier statement:

Quote:
Right all 'helpful' individuals are informed that there is no power,
the generator is running and not to go outside and energize the AC
cut-off switch. It only happens once every few years, and I don't
worry about it.


Apparently there are no 'helpful' individuals involved and you are alone
working on the wiring. So I was wasing my time and concerns.

Tim Watts
Guest

Sat Jan 05, 2019 11:45 am   



On 04/01/2019 18:43, George Herold wrote:


My point was that it's not about you, it's whether other unsuspecting
people are put in danger.

If you know there are no other people around, that is of course fine -
--
Email does not work

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