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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: frank kayser on March 09, 2018, 10:41:59 AM
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Well, the wind blew the power out last week, and my trusty Honda EU-1000 came out for lights and the fridge.
Getting power into the house used to mean a power cord through the garage door and then through the kitchen door to the garage. Of course that left a gap.
Last year I created a plug-in pass through to eliminate the problem.
OK the stage is set.
Ran my stage cords all through the house, fired up the genny, and went to test just for giggles. My stage power cords were showing red - some type of fault, but the GFCI seemed happy enough.
Plugging in my Extech tester, it said the hot neutral was reversed! Damn, I thought, I must have screwed up the pass through and reversed the black and white. No, I did not cross check it with a multimeter or a NCVT.
On my way out the door, I remembered I had a factory built extension cord plugged in for my network. I plugged in the Extech there, and it also showed reversed H-N. Well, at least it wasn't my work.
But that meant the genny was sending reversed H-N out its outlets.
I know Honda does not bond Neutral to Ground at the genny.
I also remember reading somewhere the little Honda EU-1000 acted differently than its bigger brother. I left it as is, and weathered the power outage. Now I want to know what it is that is going on.
Any help?
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Well, the wind blew the power out last week, and my trusty Honda EU-1000 came out for lights and the fridge.
Getting power into the house used to mean a power cord through the garage door and then through the kitchen door to the garage. Of course that left a gap.
Last year I created a plug-in pass through to eliminate the problem.
OK the stage is set.
Ran my stage cords all through the house, fired up the genny, and went to test just for giggles. My stage power cords were showing red - some type of fault, but the GFCI seemed happy enough.
Plugging in my Extech tester, it said the hot neutral was reversed! Damn, I thought, I must have screwed up the pass through and reversed the black and white. No, I did not cross check it with a multimeter or a NCVT.
On my way out the door, I remembered I had a factory built extension cord plugged in for my network. I plugged in the Extech there, and it also showed reversed H-N. Well, at least it wasn't my work.
But that meant the genny was sending reversed H-N out its outlets.
I know Honda does not bond Neutral to Ground at the genny.
I also remember reading somewhere the little Honda EU-1000 acted differently than its bigger brother. I left it as is, and weathered the power outage. Now I want to know what it is that is going on.
Any help?
IIRC, the single-circuit Honda EUs actually are a balanced power arrangement - 60 volts from hot to the floating ground, 60 volts from neutral. This may confuse your meter.
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Well, the wind blew the power out last week, and my trusty Honda EU-1000 came out for lights and the fridge.
Getting power into the house used to mean a power cord through the garage door and then through the kitchen door to the garage. Of course that left a gap.
Last year I created a plug-in pass through to eliminate the problem.
OK the stage is set.
Ran my stage cords all through the house, fired up the genny, and went to test just for giggles. My stage power cords were showing red - some type of fault, but the GFCI seemed happy enough.
Plugging in my Extech tester, it said the hot neutral was reversed! Damn, I thought, I must have screwed up the pass through and reversed the black and white. No, I did not cross check it with a multimeter or a NCVT.
On my way out the door, I remembered I had a factory built extension cord plugged in for my network. I plugged in the Extech there, and it also showed reversed H-N. Well, at least it wasn't my work.
But that meant the genny was sending reversed H-N out its outlets.
I know Honda does not bond Neutral to Ground at the genny.
I also remember reading somewhere the little Honda EU-1000 acted differently than its bigger brother. I left it as is, and weathered the power outage. Now I want to know what it is that is going on.
Any help?
Not the answer to your question Frank but I run my gennys in the outside screened porch and then have the cables come into the house through a sash window. I cut a piece of dense rubber foam to run along the length of the window ledge and cut a small hole in it for the cable to pass through. I pull the window down to compress the foam and the seal is perfect.
Of course it isn't a good security measure but I only use this system when I am home to monitor the generators.
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IIRC, the single-circuit Honda EUs actually are a balanced power arrangement - 60 volts from hot to the floating ground, 60 volts from neutral. This may confuse your meter.
Thanks, TJ. I believe that is what I read some time ago here. I'll have to throw a meter on the genny to verify. Another reason why a multimeter is our best friend.
A backup question, if you please - the neutral-ground bonding plug that Mike Sokol has talked about here and on the RV forums does not seem appropriate on this particular genny. Does that sound right?
Not the answer to your question Frank but I run my gennys in the outside screened porch and then have the cables come into the house through a sash window. I cut a piece of dense rubber foam to run along the length of the window ledge and cut a small hole in it for the cable to pass through. I pull the window down to compress the foam and the seal is perfect.
Of course it isn't a good security measure but I only use this system when I am home to monitor the generators.
Thanks, Debbie. Good plan. That assumes that I am as prepared as you! (or as smart!) Proof in the pudding: years ago, they were relining the water main on my street. Normally a hose is run from the temporary water main to an outside faucet to temporarily supply the house. I have a one-way valve on the feeder line blocking incoming water, so that plan to feed the house had to be adjusted. They fed the hose through the front window to the water meter. I don't remember sealing the window with foam strips or securing the window for the couple weeks it took from beginning to end. I must have put something on the window to keep the bugs out but... Cardboard, maybe? Certainly not a good sealing foam!
There will be other times and places where I will use your foam trick... Thanks Debbie!
So, maybe an info trade?
As for security - a 2x2 or something similar fit snugly between the top of the bottom sash and the upper window frame will keep the window from going up. Gaff tape it in place so anyone trying to shake it out of place to gain entry will have to spend too much time getting around your "security package" and will look elsewhere. Two sticks may be better than one...
Of course, if the top sash is movable a slight adjustment needs to be devised. Maybe a small bracket screwed to the top sash where the stick could secure both windows.
Sometimes indirect answers give as much utility as an answer that is narrowly focused on the problem.
frank
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Thanks, TJ. I believe that is what I read some time ago here. I'll have to throw a meter on the genny to verify. Another reason why a multimeter is our best friend.
A backup question, if you please - the neutral-ground bonding plug that Mike Sokol has talked about here and on the RV forums does not seem appropriate on this particular genny. Does that sound right?
If it indeed has 60/60-volt balanced power, then you'll get really strange readings with any 3-light outlet tester, and a G-N shorting plug will just short the generator output. I've seen this 60/60 split power on some cheap Chinese inverters, but never on a Honda generator. Still, anything's possible with generator manufacturers.
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Here's the thing-on ANY electrical supply supplying 120V power the thing that makes a neutral a neutral is a "Ground-neutral" bond. The NEC actually uses the term "grounded conductor" not neutral. On a 240 volt "split" phase service typical of resi and commercial single phase power, it is critical that the "grounded conductor" be connected to the center tap of the transformer to get the correct voltages. If you have only a 120 volt supply, then nothing is neutral until a bond makes it a neutral.
Honestly, if there is no bonding to ground, I don't see how it can be "balanced" power as there is no reference point. It would be interesting to check the voltage to ground from each side of the receptacle and monitor it as loads change. If is more or less a "rock steady" 60 VAC, then I would consider it balanced. My guess is that you will see it float around.
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Honestly, if there is no bonding to ground, I don't see how it can be "balanced" power as there is no reference point.
The same way your microphone is balanced without a reference point.
If your power supply is connected to ground, either center tapped or side tapped, it is by definition unbalanced. For center tapped, you have two unbalanced power supplies that happen to be opposite voltage relative to the grounded tap.
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I did a fair amount of research on the EUs 6 or 7 years ago, but it’s been quite a while, and I don’t regularly use the single-circuit ones, so I could be all wet, but here is what I remember:
The neutral is unbounded to ground. In a small system, there are pros and cons to this - the major con is you’ll never trip the circuit breaker if you have a hot->ground fault. The upside is that if you only have a single fault - hot->ground for example, as you have no hard earth reference, effectively the hot wire becomes the neutral wire and the neutral wire becomes the hot wire, so your likelihood of getting a significant shock isn’t terribly high.
Note that the above falls apart if the generator has more than one circuit like on the UE6500/7000. In larger systems, having a bonded neutral is essential (unless you’re in Europe :) ) since there are more fault current paths. Interestingly, the EU6500/7000 aren’t bonded either. The reason for this is their frequent use as home backup generators, where creating a second ground->neutral bond (the first is in your home breaker panel) causes a safety issue. For portable use, the larger EUs should absolutely be bonded - ideally inside the generator, which Honda doesn’t provide an easy means of doing, or on the generator - a dummy Edison plug with a jumper between neutral and ground.
Back to the EU1000/2000 - I don’t remember if the EU actually derives its power via two 60 volt windings/inverter channels relative to the chassis or if the earth ground is impedance balanced by a couple capacitors, but in either case, this will screw up the various all-in-one outlet testers. A real multi-meter will reveal the truth. Please test and report back.
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Honestly, if there is no bonding to ground, I don't see how it can be "balanced" power as there is no reference point. It would be interesting to check the voltage to ground from each side of the receptacle and monitor it as loads change. If is more or less a "rock steady" 60 VAC, then I would consider it balanced. My guess is that you will see it float around.
Capacitor coupling will sink enough current to confuse a typical high-impedance meter (and shock you for that matter - lots of cheap ungrounded wall-warts put 60v on the negative terminal which is enough to feel if your other hand is on something with a good ground path). A meter with a low-impedance measurement mode will provide a better view of reality.
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Looking at the internal wiring diagram, there is no connection between the inverter and ground. The AC output is floating. Also worth noting The synchronizing jacks and the kit for them is not polarized. this means that when two generators are synchronized the "neutral" (longer slot on the outlet) can be at the same potential (Hard wired) to the "hot" or shorter slot on the outlet of the second generator.
The outlets of two generators can be reversed
So if you bonded the "neutral on one generator to ground. you have a 50% chance that you have bonded the "hot" of the second generator to ground.
(http://www.wiringdiagrams21.com/wp-content/uploads/2013/10/HondaEU1000iGeneratorWiringDiagram.jpg)
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Thanks, Debbie. Good plan. That assumes that I am as prepared as you! (or as smart!) Proof in the pudding: years ago, they were relining the water main on my street. Normally a hose is run from the temporary water main to an outside faucet to temporarily supply the house. I have a one-way valve on the feeder line blocking incoming water, so that plan to feed the house had to be adjusted. They fed the hose through the front window to the water meter. I don't remember sealing the window with foam strips or securing the window for the couple weeks it took from beginning to end. I must have put something on the window to keep the bugs out but... Cardboard, maybe? Certainly not a good sealing foam!
There will be other times and places where I will use your foam trick... Thanks Debbie!
So, maybe an info trade?
As for security - a 2x2 or something similar fit snugly between the top of the bottom sash and the upper window frame will keep the window from going up. Gaff tape it in place so anyone trying to shake it out of place to gain entry will have to spend too much time getting around your "security package" and will look elsewhere. Two sticks may be better than one...
Of course, if the top sash is movable a slight adjustment needs to be devised. Maybe a small bracket screwed to the top sash where the stick could secure both windows.
Sometimes indirect answers give as much utility as an answer that is narrowly focused on the problem.
frank
The 2x2 fix is a good idea Frank.
I have a sash window in my garage and I keep an AC/dehumidifier in there for the humid summer months - not a window unit but a portable wheeled unit.
The venting plate which allows the vent hoses to exit the house go through the plate. I do the same thing with that set up - I close the sash window down onto the plate using a long piece of foam.
However, because that window does get left open when I am away, I have screwed a couple of L shaped brackets into the upper window which prevents the lower one from being opened. When the humidity and heat drops, I remove the plate and close and lock the window. Wash and repeat seasonally.
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Looking at the internal wiring diagram, there is no connection between the inverter and ground. The AC output is floating. Also worth noting The synchronizing jacks and the kit for them is not polarized. this means that when two generators are synchronized the "neutral" (longer slot on the outlet) can be at the same potential (Hard wired) to the "hot" or shorter slot on the outlet of the second generator.
The outlets of two generators can be reversed
So if you bonded the "neutral on one generator to ground. you have a 50% chance that you have bonded the "hot" of the second generator to ground.
I'll add that, if the output of a generator is not bonded to a zero-voltage reference (ground/frame), then calling one pole "hot" and the other "neutral" is entirely arbitrary, and determined only by the position of the slots of the receptacle.
On the other hand, if the generator outputs dual voltage (120/240), then we can more correctly call the center tap "neutral". I'm not aware of a dual voltage generator without a zero reference bond (aka "ground" or the generator frame), so calling it neutral really isn't so arbitrary after all.
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This is generally a non issue because both line and neutral are floating inside modern gear.
You can measure what is going on crudely but setting VOM to AC volts (not amps :o ). Touch one probe lead with your first hand while probing with the other... If both sides are hot you will measure some modest AC voltage on both.
You can do the same thing with a neon lamp probe but 60V may be marginal low for them to light up.
JR
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They are indeed 60 Volts hot to ground and 60 Volts neutral to ground. I've measured them many times to verify when I puck them up from a rental shop.
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Looking at the internal wiring diagram, there is no connection between the inverter and ground. The AC output is floating. Also worth noting The synchronizing jacks and the kit for them is not polarized. this means that when two generators are synchronized the "neutral" (longer slot on the outlet) can be at the same potential (Hard wired) to the "hot" or shorter slot on the outlet of the second generator.
Frank is 100% correct. In fact, the Honda parallel kits that I've seen don't even have a way to know which lead is neural and which one is hot. So there really is a 50/50 chance of having the neutral and hot sides of the Edison outlets reversed on the two generators. Not really dangerous, but certainly something to be aware of when doing something like using a dummy G-N bonding plug or general measurements using 3-light outlet testers, etc....
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The balanced power of 60 v hot and 60 v neutral is the same as the navy so The ground rod is needed. There is no neutral in actuality on this balanced power. You will also need a two pole power switch to turn off the power to a device. GFI may not protect you from problems in balanced power because it is designed for unbalanced power. Mike this might be an important safety that needs to be tested. How will GFI respond with 60 volt power.
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The balanced power of 60 v hot and 60 v neutral is the same as the navy so The ground rod is needed. There is no neutral in actuality on this balanced power. You will also need a two pole power switch to turn off the power to a device. GFI may not protect you from problems in balanced power because it is designed for unbalanced power. Mike this might be an important safety that needs to be tested. How will GFI respond with 60 volt power.
GFCI compares the net of line current vs neutral current, so is agnostic about 120V - 0V, and +60v -(-60v). As long as the current in the line-neutral loop nets out to null, the GFCI is happy.
JR
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Ok so when the single pole power switch turns off the power to the amp and the neutral is still able to push -60 v. will it shut down or continue to flow.
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Ok so when the single pole power switch turns off the power to the amp and the neutral is still able to push -60 v. will it shut down or continue to flow.
The power is floating. It has no relation to ground at all. You can not light a 32 volt or a 60 volt light bulb between either side and ground. When you open a single pole switch to a amp the amp goes off because there is no current path. No complete circuit.
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Frank is 100% correct. In fact, the Honda parallel kits that I've seen don't even have a way to know which lead is neural and which one is hot. So there really is a 50/50 chance of having the neutral and hot sides of the Edison outlets reversed on the two generators. Not really dangerous, but certainly something to be aware of when doing something like using a dummy G-N bonding plug or general measurements using 3-light outlet testers, etc....
Or using vintage gear that has one side of the line connected to the chassis. How does Honda get a design like this UL listed? I get the genny and the floating supply-you can debate endlessly the safety aspect of floating vs grounded and generally using only one or at best 2 modern "appliances" it is going to be relatively safe using a floating ground. But when you start interconnecting things like is usually done with sound gear the safety issue becomes a concern, IMO.
There have been more than a few documented instances of reversed wiring in factory power cords. And as soon as there is a fault to ground from either conductor, you now have a grounded system that may or may not have overload protection in the right places.
If you use these in parallel to set up a sound system, you really need to understand how to properly set them up and take the time to meter everything according to TJs procedure as discussed in another thread.
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Or using vintage gear that has one side of the line connected to the chassis.
Stinger caps are "caps" so non lethal currents involved. "Hot chassis" products had chassis insulated from human contact.
How does Honda get a design like this UL listed?
UL does not approve mingling grounds with neutral, but it is pretty much by the book (their book).
I get the genny and the floating supply-you can debate endlessly the safety aspect of floating vs grounded and generally using only one or at best 2 modern "appliances" it is going to be relatively safe using a floating ground. But when you start interconnecting things like is usually done with sound gear the safety issue becomes a concern, IMO.
There have been more than a few documented instances of reversed wiring in factory power cords. And as soon as there is a fault to ground from either conductor, you now have a grounded system that may or may not have overload protection in the right places.
reversed line and neutral is generally harmless... I only experienced one (borrowed) extension cord with line and ground swapped, and that was clearly a human fault (not mine, but I should have metered it before using it).
If you use these in parallel to set up a sound system, you really need to understand how to properly set them up and take the time to meter everything according to TJs procedure as discussed in another thread.
Another reason to never bootleg grounds to neutral...
JR
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Or using vintage gear that has one side of the line connected to the chassis. How does Honda get a design like this UL listed? I get the genny and the floating supply-you can debate endlessly the safety aspect of floating vs grounded and generally using only one or at best 2 modern "appliances" it is going to be relatively safe using a floating ground. But when you start interconnecting things like is usually done with sound gear the safety issue becomes a concern, IMO.
There have been more than a few documented instances of reversed wiring in factory power cords. And as soon as there is a fault to ground from either conductor, you now have a grounded system that may or may not have overload protection in the right places.
If you use these in parallel to set up a sound system, you really need to understand how to properly set them up and take the time to meter everything according to TJs procedure as discussed in another thread.
The big thing I see with these sorts of generators is that they are NOT designed to be connected to any sort of infrastructure.
The design is only for cord operated tools etc. I expect they think of vintage gear as 1990s drills, sanders and the like.
Sent from my iPad using Tapatalk Pro
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these generators are great for sound systems because the power is true sine wave and clean and you can parallel them.
I agree completely that you need to know how they are wired and make sure you have the hot, neutral, and ground that you think you should. I talked with a guy who knows his stuff and uses a number of them for a large RV and desplay trailer. He has a custom distro and ground rod setup so he can get them to do what he wants.
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I agree completely that you need to know how they are wired and make sure you have the hot, neutral, and ground that you think you should. I talked with a guy who knows his stuff and uses a number of them for a large RV and desplay trailer. He has a custom distro and ground rod setup so he can get them to do what he wants.
Hot, Neutral, and Ground, in balanced power does not exist. V+, V-, and ground. Transformer is wound with coil with two ends and center tap. Same way you use a 1:1 transformer to get balanced mic or line to unbalanced.
On the output of a bridged amp we connect the two postive leads to the speaker. If you use a 1/4 TS into the speaker your body is exposed to the Voltage and Current available from the amps power rails. This is why Speakon removed the Sleave from contact. This two is balanced power.
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Hot, Neutral, and Ground, in balanced power does not exist. V+, V-, and ground. Transformer is wound with coil with two ends and center tap. Same way you use a 1:1 transformer to get balanced mic or line to unbalanced.
On the output of a bridged amp we connect the two postive leads to the speaker. If you use a 1/4 TS into the speaker your body is exposed to the Voltage and Current available from the amps power rails. This is why Speakon removed the Sleave from contact. This two is balanced power.
I should have put the words Hot and Neutral in quotes. I was referring to what we assume is "hot" and "neutral" based on the outlet mounted on the generator. We tend to think of the longer slot on a outlet as being the "Neutral" and much more important, we might expect the long slot on one outlet to be at the same potential as the long slot on the outlet on the other generator if we have them paralleled. This is not necessarily the case. They can be 120 volts AC apart or we can test them and make them the same. Also there is no reference to ground at all. No center tap or any other tap. The AC output is not related to ground at all. You can tie the ground on the generator to either the long slot "Neutral" or the the short slot "Hot" or to some other reference. For example, I don't know why anyone would but you could tie the safety ground on the generator to a ground rod and to the skin on your RV, and tie the long slot or "neutral" to the 12 volt positive terminal on the RV battery.
This is what you might expect but not get unless you make it so.
(http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elepic/recept.gif)
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The NEC states that the 'Neutral' is the grounded current carrying conductor. So using a white wire or connecting to a terminal labeled Neutral doesn't make it a Neutral conductor.