whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
 ·Earthlink Cable Mo..
1 edit | reply to steve1515
Re: Whole House Surge Protector?
quote:
So, you are saying that this is not a series device?
Don't think so, other than fuses if it has them, but I don't believe it does.
Like all other surge protectors I've seen, its goal is to 'shunt' transients to ground; hence the ground wire.
The meter-pan SPD in your link is not UL listed as a 'primary protector', but rather is listed as a 'secondary protector'. Thus it doesn't even meet the UL requirements for protecting your service entrance, although that is what the mfr wants you to think. Perhaps there is not enough room in the socket for the heavy-duty components necessary for primary protection rated equipment.
The meter pan SPD is only rated at 10kAIC short circuit current, which will violate utility company requirements if they require 20kAIC (Which could be disastrous should you have a short circuit between the meter pan and your main circuit breaker).
Better suggestion - get a 'whole house' surge protection device that attaches to a two-pole circuit breaker in your main panel board, and is rated as a 'primary protector', and thus is beefy enough to really protect your system. Square 'D' and Current Technologies make good one. And make sure your electrician keeps the wires between the panel board and the device as short as possible, ideally the length of the leads that come with the device (this is very important). Believe it or not, the gauge is not as important. Use a #6 minimum ground wire.
Square-D and Current Technology make very good whole-house SPDs:
Square-D
Current Technology |
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ArthurS
Watch Those Blinking Lights
Premium
join:2000-10-28
Hamilton, ON
| reply to SparkChaser
said by SparkChaser  :Terms check  by isolated ground, do you mean a single (undisturbed) ground from the outlet to the panel? More to it than that. You need an isolated ground receptacle as well as an insulated grounding conductor. This separate, insulated ground conductor is run with the hot and neutral to the receptacle and connected directly to the isolation ground terminal. The wallbox that houses this isolated ground receptacle still needs to be bonded to building ground, but is kept separate from the ground terminal on the isolated ground receptacle. Inside the breaker subpanel you will typically find a separate isolation ground bus bar (might be in a separate compartment) that is insulated/isolated from the panel case, with a grounding conductor that bonds it to the main ground for your electrical service.
In essence, your isolation ground provides a insulated, direct path from the receptacle isolation ground terminal to the main ground of your electrical service. With the technical power systems I design for professional audio, I have very specific requirements on the wire resistance/ ground conductor size to minimize noise in the system, and I require the electrical contractor to test the integrity of the main building ground. I have a spendy AC circuit tester that plugs into a isolation ground receptacle, I sometimes catch a few "short cuts" that a few electricians have taken in wiring up isolation ground receptacles, all it takes is one inadvertent short to building ground (other than the connection made at the main electrical service), or a mis-wired junction to bring the integrity of an entire isolation ground system down the toilet! |
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steve1515
Premium
join:2000-08-07
Peabody, MA
 ·Speakeasy
| said by ArthurS :said by SparkChaser :Terms check by isolated ground, do you mean a single (undisturbed) ground from the outlet to the panel? More to it than that. You need an isolated ground receptacle as well as an insulated grounding conductor. This separate, insulated ground conductor is run with the hot and neutral to the receptacle and connected directly to the isolation ground terminal. The wallbox that houses this isolated ground receptacle still needs to be bonded to building ground, but is kept separate from the ground terminal on the isolated ground receptacle. Inside the breaker subpanel you will typically find a separate isolation ground bus bar (might be in a separate compartment) that is insulated/isolated from the panel case, with a grounding conductor that bonds it to the main ground for your electrical service. In essence, your isolation ground provides a insulated, direct path from the receptacle isolation ground terminal to the main ground of your electrical service. With the technical power systems I design for professional audio, I have very specific requirements on the wire resistance/ ground conductor size to minimize noise in the system, and I require the electrical contractor to test the integrity of the main building ground. I have a spendy AC circuit tester that plugs into a isolation ground receptacle, I sometimes catch a few "short cuts" that a few electricians have taken in wiring up isolation ground receptacles, all it takes is one inadvertent short to building ground (other than the connection made at the main electrical service), or a mis-wired junction to bring the integrity of an entire isolation ground system down the toilet! Can you get pics of the isolated ground installations? I'd like to see this stuff. |
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ArthurS
Watch Those Blinking Lights
Premium
join:2000-10-28
Hamilton, ON
| Hmmm, I would have to do a lot of digging to find pictures of completed system, but here is a great pic of a sequencing technical power panel with a separate isolation ground compartment (on the right side). For my systems I always go with a single phase three wire panel instead of the three phase panel shown.
Attached you will find a detail from my technical power drawing set showing what's involved in wiring an isolation ground receptacle. |
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SparkChaser
BURY BECK
Premium
join:2000-06-06
Downingtown, PA
 ·Verizon FIOS
·Comcast
| reply to ArthurS
said by ArthurS :More to it than that. You need an isolated ground receptacle as well as an insulated grounding conductor. Doh! I forgot about the receptical. I didn't even know they made them  good explaination and pics.
The purpose of this kind of system is to keep any building noise on the ground system isolated from the ground on your equipment, is that the idea?
Thanks for the education
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SparkChaser
BURY BECK
Premium
join:2000-06-06
Downingtown, PA
·Verizon FIOS
·Comcast
| reply to whizkid3
Wow a selenium stack! I haven't seen those in a lot of years  Do you know how Current Technology is using it? I couldn't find anything on the site. Also, I wonder if their filtering affects line signaling devices like X10.
Interesting link.
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My computer has more memory than I do!
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whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
·Earthlink Cable Mo..
| reply to steve1515
IMHO, Current Technology makes the best SPDs on the market. You can tell simply by their specs. I have been to a few technical presentations by them on SPDs. They have perhaps the best SPD testing lab in the country, and love to blow these things up. In the process, they have learned how to build the best.
Don't know the ansers to your questions, though. |
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Splitpair
Premium
join:2000-07-29
Cow Towne
 ·T-Mobile US
| reply to ArthurS
said by ArthurS :I have a spendy AC circuit tester that plugs into a isolation ground receptacle, I sometimes catch a few "short cuts" that a few electricians have taken in wiring up isolation ground receptacles, Isolated ground receptacles grrrrrrrr.
If I had a buck for every time I caught a cub electrician bonding the isolated ground to the metallic box I would buy you all a round.
But what really pisses off the Good Humor Man is when the electrical inspector red tags the work for not being bonded.
Then you have two options go before the BRA and have the inspector over-ruled (maybe a 30 day process) or get the permit signed off and rip out the bonds now that's profitable.
P.S. It's rumored that in Miami-Dade County they have the best inspectors money can buy so that sort of adds a third option.
»www.miami.com/mld/miamiherald/ne···0702.htm
Wayne
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If you cannot fix it with a buttset and some beanies you ain't a technician. |
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Splitpair
Premium
join:2000-07-29
Cow Towne
·T-Mobile US
| reply to whizkid3
said by whizkid3 : The meter-pan SPD in your link is not UL listed as a 'primary protector', but rather is listed as a 'secondary protector'. Thus it doesn't even meet the UL requirements for protecting your service entrance, although that is what the mfr wants you to think. Well it is the same exact device Florida Power & Light is leasing to their subscribers for $8.95 per month. I got the link and model off the side of the one my next door neighbor installed.
Wayne
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If you cannot fix it with a buttset and some beanies you ain't a technician. |
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steve1515
Premium
join:2000-08-07
Peabody, MA
·Speakeasy
| reply to ArthurS
Cool pictures!
I have a few questions...
So when installing isolated ground receptacles, each one must have a separate ground that goes back to the panel? Or, can you connect the isolated ground from one plug to the isolated ground of the next outlet down the line as long as you don't bond it to the regular ground?
In the diagram, you're using the the metallic conduit as a regular ground. Can you just use regular cable and add a fourth wire for the regular ground instead? What about using plastic boxes and leaving out the fourth regular ground wire?
What's a sequencing panel? I've never seen one before. It looks like the breakers are outputting low voltage, but without a transformer. How do these things panels work? |
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whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
·Earthlink Cable Mo..
| quote:
Well it is the same exact device Florida Power & Light is leasing to their subscribers for $8.95 per month. I got the link and model off the side of the one my next door neighbor installed.
So? Sounds like they are making a fortune. Obviously, FP&L requires only a 10KAIC rating. Still not a very good SPD for service entrance, regardless of who is selling or leasing them.
said by steve1515 :So when installing isolated ground receptacles, each one must have a separate ground that goes back to the panel?
Yes. Its the best way to do it, rather than daisy chaining the ckts together. You can also 'home run' the isolated grounds. quote:
Or, can you connect the isolated ground from one plug to the isolated ground of the next outlet down the line as long as you don't bond it to the regular ground?
Yes, not the best, though. quote:
In the diagram, you're using the the metallic conduit as a regular ground. Can you just use regular cable and add a fourth wire for the regular ground instead?
Yes. You'll have to have a green wire, and a green with yellow stripe wire. (Or you can tag one of the green wires at every box with a yellow stripe.) quote:
What about using plastic boxes and leaving out the fourth regular ground wire?
Its not unlawful. But you will lose any of the big advantages of noise reduction from having the isolated ground inside of a grounded conduit (shield). |
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ArthurS
Watch Those Blinking Lights
Premium
join:2000-10-28
Hamilton, ON
| reply to SparkChaser
said by SparkChaser :The purpose of this kind of system is to keep any building noise on the ground system isolated from the ground on your equipment, is that the idea? Thanks for the education Yes, that's one reason, the other is to keep all grounds at the same plane, ideally as close to the main building ground as possible. Careful management of the resistance of the ground conductor must be followed, which is why on very sensitive systems you will find a very large wire gauge (00 gauge) being used between the main isolation ground buss bar and the main grounding point. On longer runs I will insist on a large gauge wire to the receptacle.
Having all your electronic equipment on the same ground plane (consider that most electronic equipment has it's chassis connected to ground) helps keep noise potential on interconnecting wiring to a minimum. This particularly holds true with professional audio and video equipment, where ground loops can be troublesome if equipment chassis are at different ground potentials. |
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ArthurS
Watch Those Blinking Lights
Premium
join:2000-10-28
Hamilton, ON
| reply to steve1515
said by steve1515 :Cool pictures! I have a few questions... So when installing isolated ground receptacles, each one must have a separate ground that goes back to the panel? Or, can you connect the isolated ground from one plug to the isolated ground of the next outlet down the line as long as you don't bond it to the regular ground? Each receptacle should have it's own separate isolation ground conductor that goes back to the panel, however if two immediately adjacent receptacles are sharing the same circuit, it is acceptable in some cases to "daisy-chain" the isolation ground conductor to another isolation ground receptacle as long as the electrician is careful to preserve the integrity of the isolation ground.
said by steve1515 :In the diagram, you're using the the metallic conduit as a regular ground. Can you just use regular cable and add a fourth wire for the regular ground instead? What about using plastic boxes and leaving out the fourth regular ground wire? Yes to both cases, and in the case of a separate non-insulated ground conductor bonded to the metal back box, it provides an extra layer of protection, and may appease the demands of an electrical inspector. I prefer the use of EMT conduit and metal boxes over plastic ones since the layer of metal helps with shielding.
said by steve1515 :What's a sequencing panel? I've never seen one before. It looks like the breakers are outputting low voltage, but without a transformer. How do these things panels work? Sequencing panels are a very unique product, I use them to turn my professional audio systems on and off in a certain sequence to prevent any loud "bangs" that may ruin the loudspeakers. Mixer on first, amps on last, amps off first, mixer off last. The breakers in this panel are motorized, using a low voltage relay system (the circuit boards on the left compartment) to turn on/off each individual AC circuit breaker. Other than the "special" breakers, this is an ordinary Square-D panel with two separate side boxes attached, in fact there may be a bunch of circuits within this panel that remain on at all times, and are not part of a sequenced on/off. There are some fancy added features, including an immediate shut down when a fire alarm is activated, or a properly sequenced system turn on should power be restored after an electrical outage. You can "daisy chain" these sequencing panels with other similar panels, and remotely control them as well. |
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steve1515
Premium
join:2000-08-07
Peabody, MA
·Speakeasy
| reply to steve1515
I see.
So, how do these breakers know that you turned on the mixer so that they can turn on the amps.
I was looking at that panel in the picture and it looks like there are many breakers/circuits available, but there are very few terminals for neutral connections. Strange. Maybe I'm looking at it the wrong way.
A few more questions about the isolated ground stuff...
How does it work with a sub panel? Do you still have to run the isolated ground back to the main panel even though the circuit breaker is in a sub panel?
If you only have a main panel and no sub panels, can you just bond the isolated grounds to the regular ground & neutral bus? Wouldn't it be the same as having a separate one right next to it and bonding both buses? |
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ArthurS
Watch Those Blinking Lights
Premium
join:2000-10-28
Hamilton, ON
| said by steve1515 :I see. So, how do these breakers know that you turned on the mixer so that they can turn on the amps. It doesn't know anything about the operation of the system, it simply provides an elegant solution for AC power and power sequencing. In the control booth you have one of these remote control switches to turn the system on or off, which is manually controlled by the operator. It even has a key switch to prevent the custodians from cranking the system late at night! 
said by steve1515 :I was looking at that panel in the picture and it looks like there are many breakers/circuits available, but there are very few terminals for neutral connections. Strange. Maybe I'm looking at it the wrong way. It is a standard Square D load centre, they added on the low voltage control compartment and the isolation ground compartment, but have not subtracted anything from the load centre itself (it has to meet code requirements). I have never received any complaints from electricians that they were short on neutral buss bar space.
said by steve1515 :A few more questions about the isolated ground stuff... How does it work with a sub panel? Do you still have to run the isolated ground back to the main panel even though the circuit breaker is in a sub panel? The isolation ground systems I design follow a star topology with sub panels, so from the *main* system isolation ground buss bar, a very heavy gauge copper wire is run to the sub panel isolation ground buss bar, and from there isolation ground is routed to receptacles serviced by the sub panel. It all comes down to keeping wire resistance as low as possible.
said by steve1515 :If you only have a main panel and no sub panels, can you just bond the isolated grounds to the regular ground & neutral bus? Wouldn't it be the same as having a separate one right next to it and bonding both buses? Ultimately the isolation ground must be bonded to the neutral and building ground at *one* point, and one point only. On smaller systems, this may be the main grounding rod(s) for the entire building, on larger systems serviced by an isolation transformer, the isolation ground gets bonded to the neutral and ground at the transformer. One way or another, isolation ground must meet neutral and regular ground, but the key here is it must meet it at one point only, and that the wire resistance is as low as possible to keep the ground plane low and noise to an absolute minimum. |
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91439306
15,000 Watts of Bass Power
join:2002-10-16
New Milford, CT
| And how! This last point is absolutely true and I had a very effective demonstration of it when I converted my sound system racks' electrical system over to 240 split phase. For kicks, I tried it with the existing 3-wire cable, but because the safety ground and neutral wires were bonded at the outlet, the system produced a very loud 60Hz hum when powered on.
Upon running a new 4-wire cable across the studio auditorium to the breaker panel, and isolating the grounds from eachother, the hum was vanquished. I wish I could have had the foresite to videotape that effect and include it in an expert opinion before a court, or before some of these building inspectors who insist on bonding at the outlets...
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steve1515
Premium
join:2000-08-07
Peabody, MA
1 edit | Ground (isolated or not) and neutral should never be bonded at the outlet. I don't think those inspectors know what they're doing. |
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whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
·Earthlink Cable Mo..
2 edits | reply to steve1515
quote:
How does it work with a sub panel? Do you still have to run the isolated ground back to the main panel even though the circuit breaker is in a sub panel?
Yes. You must have a separate isolated ground bus in each sub-panel, insulated from contact with the metal panel. The isolated ground system is kept isolated except at the point where the main building grounding electrode system (your ground rods, etc) is bonded to the equipment safety ground system.
quote:
If you only have a main panel and no sub panels, can you just bond the isolated grounds to the regular ground & neutral bus? Wouldn't it be the same as having a separate one right next to it and bonding both buses?
No, you can not. You must have a separate isolated ground bus bar. Is it the same? No, not exactly.
Of course, as Arthur S. described, things are different when you have a separately derrived source (i.e. the case of the isolation transformer he discussed is one example.) |
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signmeuptoo
Folding and Crunching Not just Breakfast
Premium
join:2001-11-22
LOSTinSpace
clubs: 
 ·Future Nine Corpor..
·AT&T Southeast
1 edit | reply to ArthurS
said by ArthurS :Hmmm, I would have to do a lot of digging to find pictures of completed system, but here is a great pic of a sequencing technical power panel with a separate isolation ground compartment (on the right side). For my systems I always go with a single phase three wire panel instead of the three phase panel shown. Attached you will find a detail from my technical power drawing set showing what's involved in wiring an isolation ground receptacle. In that zip file, the annotation to the diagram, item #9:
A question, they are talking about a three phase system there, right? So that bond/run #9 is to the Neutral Bus with the connection to the service feed? If so, then #9 doesn't apply to us in residences, right? Or does it, because I am wondering how dangerous it might be to misinterpret that and use the house neutral that way...
Also, in the image you posted: I assume, as I don't know ANYTHING about Commerical electrical installations, that the reason that is called an "isolation" is becuase you are saying the the ground bus is in a totally separate compartment with the bus in it, instead of in the distribution panel? If so, you are saying that we want to get our own little box with a ground bus and make it a secondary isolated ground bus box? I am a bit unclear on what you are saying, I apologize for being so dense!
Could you create a schematic or graphic, please?
Edit:
So after all is said and done, these are the devices that are most advisable for a home owner to install:(?)
»https://currenttechnology.com/product.xh···entGuard
Thanks.
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whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
·Earthlink Cable Mo..
| reply to steve1515
quote:
because the safety ground and neutral wires were bonded at the outlet...
This is a verybad idea. The safety ground and neutral are never to be bonded (connected together) at the outlet. They are only supposed to be bonded together at one place, the enclosure containing main disconnect switch/circuit breaker, where the grounding electrode system is also connected.
Having them connected at the outlet is a fire and an electrocution hazzard. |
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