So I was installing an complete system and I had all my inbound breakers shut off on the system. My spd-300 ac was wired in properly. I wired my cord onto the panel after I wired the spd in place. Turned thebsystem on to put power to the house. Off grid system battery power. So I was wiring the cord onto the panel for the generator in. All good. So I was then working the plug end onto the cord. Mind you I have the breakers for ac-in flipped off. The neutral touches the positive, which should not matter because everything is in the off position that the cord is wired to. It arc and killed thebspd device. So here is my real problem. Why am I getting power still on the ac-in port? The plug is not connected to anything and the breakers are all off? The spd is transferring 91v ac over to the other side of the panel board? Why is this even available for people to buy? And if this is how the spd works, then what is the point of connecting it up to my inverter because it is introducing power to both sides of my inverter if that is the case? I am used to getting shocked, it is just a little tingle in the fingers, but the $100+ it cost me because it is sending power to the ac-in. Also now since it has shut off the blue light on the devise it still is passing 91v of ac current thru it from the ac-out panel thru the spd and back to the ac-in.
That is my question.
Please inform me and everyone else to why so we all learn from my do's and dont's.
Thanks
The Ugly One
The Manual:
http://www.midnitesolar.com/pdfs/SPD_Installation_Manual.pdf
Switch OFF, ALL breakers in a panel when working on it. Switch the main disconnect, and all other sources of power, before doing any work on any power system.
EDIT, from the above SPD manual,
" … DANGER: Electrical shock or burn hazard. Installation of this SPD should only be done by qualified personnel. Failure to lockout electrical power during installation or maintenance can result in fatal electrocution or severe burns. … "<
If you are not comfortable with your knowledge, or competence, hire a competent, Licensed Professional.
Did not exactly understand what happened, but it seems that you made several mistakes.
Just all IMO. Please DO be careful. Power systems can KILL ! Vic
Can you make a line drawing of your system and how all that stuff is wired in - kind of hard to visualize what might have happened from what you described. Make a drawing and you can always take a photo and attach that on here in case you don't have another way to display it. Much easier to understand by looking at a schematic or line diagram.
Larry
I will and upload it.
The SPD300 should not start conducting until over 450V DC across either of the two hot lines and GND.
Before this, there may be a wee bit of leakage at some voltage below this. It may be enough to measure with a high input impedance volt meter but very very little current should be available until a fairly high voltage.
Looking at your hookup, as the others are wondering about, may give a clue.
If the SPD was fully conducting at 120VAC or 240VAC across it then maybe it really is defective ? That would be very rare but not impossible. We get VERY few SPDs back.
Hi again T U O,
While we await your diagram to be Posted, would like to mention several additional things:
It seems important to mention, that, AC voltages that are present inside panels and boses of our power, can be dangerous, and can KILL,
DC Voltages in our PV-based power systems can be considerably MORE DANGEROUS, than the AC voltage present in most residential power systems. This is because DC voltages above about 50 V can cause muscle contraction, when we contact them. This contraction often makes it difficult for we humans to disconnect our bodies from the sources of this DC voltage.
AND, it only takes a relatively small amount of current flowing through our chests to stop our hearts from beating. This can be lethal.
We do not know what is the PV voltage that is connected to the Vin of your Classic 250 CP, but on a 48 V system, this is often 85 - 105 VDC at String Vmps, on a Classic 150. Classic 250s, usually run higher Vin values. At these voltage levels it can be quite easy for DC currents that flow through our bodies, to reach lethal levels.
It appears that you envision a fairly large power system, in your future. Would suggest that you seek some expert advice, for the design, and construction of that system.
Please DO shut off ALL power sources, when doing any work on any power system. There are enough other risks to our lives, without adding more risks, by servicing power systems that are not shut off properly.
It is not possible to know exactly what happened when you were trying to wire the cord, that you mentioned in the first Post, but, it seems that you were working in a HOT panel/box.
Take care, Good luck, Vic
My phone wont allow me to upload onto this site. What do I need to do to upload image?
I am doing this on a computer so not sure how it looks on a phone but at the bottom of the Post Reply screen there is a small + that says Attachments - I click on that and can then attach a photo . If you tried it and it says your photo is too large , go into the option of your camera and make the resolution of the photo smaller take the photo again and then try attaching it.
Larry
So here is the schematic what I have installed so far. There is no classic 250s yet, we are waitting for the solar panel mounts to arrive.
Here is the plug end that goes into the epanel for the generator input. So this end would be plugged into the generator.
Hey Ugly... (that doesn't sound very nice ?!?)
I see from your drawing that your SPD (component I) is connected correctly BUT I am not sure why you are using one half of the SPD for L1 input and the other half of the same SPD for the L1 output ? Not sure why you are using an SPD for ANY of the AC outputs ?
Typically one would use a single SPD for just the L1 and L2 input lines to GND.
OK, that being said, (obviously :), the system GND should be connected at some place to the L1 and L2 NEUTRAL line. That connection itself should stop any leakage from input to output side (I think) since the center (GND/NEUTRAL) is the tie point internally of the SPD for the two halves.
Are you sure that the GND and Neutral are tied together ? And when you get the "tingle", where are the two connections you are getting the tingle from ? L1 output to ???... GND or Neutral or bare-foot on a cement floor ?
Usually you won't need to lightning protect the inside of the house... Only the AC lines coming in from the outside where lightning can get in.
But, I am wondering why you would would read that leakage voltage because of the center connection to GND/NEUTRAL.
Hi boB,
A couple of things:
The SPD Manual shows one half of an AC SPD connected to the AC IN, and the other half to the AC OUT (Fig 1.2).
And, for some reason, in the diagram below the above Figure, it also shows a 240 VAC system, where this also done (1/2 of an AC SPD connected to AC IN, the other half to that Line's AC OUT.
Personally would wire 240 VAC system SPDs as you noted, boB -- one SPD on L1 & L2 IN, and another SPD on L1 & L2 on the Output, if needed.
The inverter in this system appears to be a Sunny Island 120 VAC inverter (FWIW).
As an aside, MOVs are relatively Capacitive, which is probably toe origin of the leakage current.
FWIW, Vic
I believe I was touching the L1 in wire when I was gripping the plug to tighten down the screws. Then when I put the neutral line to slide into the plug it completed the circuit causing me to feel the tingle.
But my question is still that of why is it connecting the L1 out line to the L1 in line thru the internals of the spd?
My theory here, This is only a theory.
I do not see a Neutral to Ground bond and if not the Ground will be pulled high by the SPD. If this is off grid you should put a bond between the AC Neutral and Ground
Quote from: FNG on March 31, 2020, 08:29:53 AM
My theory here, This is only a theory.
I do not see a Neutral to Ground bond and if not the Ground will be pulled high by the SPD. If this is off grid you should put a bond between the AC Neutral and Ground
Maybe the documentation needs to have a sequence of connecting the bonded Neutral green wire connected first ?
Good point boB & Ryan, on the missing Neutral/Ground Bond. I had missed that.
The thing that I do not really understand, is doing wiring in that panel with any AC circuits powered.
We all have wired things HOT, but would bet that anyone doing that is going to be very, very, very careful, and knew well, just which parts were HOT.
IMO, Vic
Quote from: Vic on March 31, 2020, 04:48:51 PM
Good point boB & Ryan, on the missing Neutral/Ground Bond. I had missed that.
I noticed there wasn't a specific connection for the bond I think but assumed they were connected.
Quote from: Vic on March 31, 2020, 04:48:51 PM
The thing that I do not really understand, is doing wiring in that panel with any AC circuits powered.
What I do not understand is why our documentation would say to wire the L1 and L2 LOAD/OUTPUT side to an SPD ??
And especially, the SAME SPD for input and output if one wants to do that if there is an L2 to be dealt with ?? There MAY be a good reason for that though that I am not thinking of right now.
Lighting has a much higher probability of hitting the grid side than the inside of the house I would think.
You can protect the inside of the house though of course and it shouldn't hurt.... OR tingle ! :)
Realize even a Magnum inverter can run voltage between neutral and ground with no bond as they are floating, I have been bit by that one in the past
Yes, these products have small-ish capacitors from L1 and L2 to GND for their common-mode filtering.
That's usually where the AC leakage comes from without anything else like an SPD connected.
But you would normally see about half the AC line voltage between L1 and GND.
If GND and Neutral are tied together it might be different.
Quote from: Vic on March 31, 2020, 04:48:51 PM
The thing that I do not really understand, is doing wiring in that panel with any AC circuits powered.
What it was I did all the wiring inside the panel when it was dead. I didn't power up the inverter yet. It was dark and it was time to put the house ac line from generator plug to the panel. So I unplugged the house from generator. Took the plug off the wire. Wired the house into the system. Had the line for the ac-in to inverter already wired in to the panel. Had the spd already wired in. Because there was people inside without power I turned on the power. Keeping in mind that there was no more wiring to be done inside the panel. I had the ac-in breaker turned off. So to my knowledge there was no reason for my ac-in wire to have any power what so ever and now all I needed to do is put the plug end onto the ac-in to inverter wire so I could plug in the generator to send power to the inverter from generator. And while wiring the plug end to the plug that is when the spark started. And after that point I tested it with the meter and it still carried 90v from positive-negative of the live-in wire. It stayed with power up until the point where I disconnected the spd... I did all my work without power into the box or panel. My breaker that might allow back feed of power was turned off. The thing that allowed power to pass thru the system to the line that shocked me was the connection inside the spd. So in my mind the spd was faulty and it put me into the situation of being hurt/injured. (My pride is hurtn I am not hurt.) So i should of said from the get go in better wording how i was working. Is their a true schematic of the spd that we can look over to see what may of done this? I would disassemble the unit but I want to get a replacement if it was truly defective.
Quote from: The Ugly One on April 01, 2020, 05:01:38 PM
Quote from: Vic on March 31, 2020, 04:48:51 PM
The thing that I do not really understand, is doing wiring in that panel with any AC circuits powered.
What it was I did all the wiring inside the panel when it was dead. I didn't power up the inverter yet. It was dark and it was time to put the house ac line from generator plug to the panel. So I unplugged the house from generator. Took the plug off the wire. Wired the house into the system. Had the line for the ac-in to inverter already wired in to the panel. Had the spd already wired in. Because there was people inside without power I turned on the power. Keeping in mind that there was no more wiring to be done inside the panel. I had the ac-in breaker turned off. So to my knowledge there was no reason for my ac-in wire to have any power what so ever and now all I needed to do is put the plug end onto the ac-in to inverter wire so I could plug in the generator to send power to the inverter from generator. And while wiring the plug end to the plug that is when the spark started. And after that point I tested it with the meter and it still carried 90v from positive-negative of the live-in wire. It stayed with power up until the point where I disconnected the spd... I did all my work without power into the box or panel. My breaker that might allow back feed of power was turned off. The thing that allowed power to pass thru the system to the line that shocked me was the connection inside the spd. So in my mind the spd was faulty and it put me into the situation of being hurt/injured. (My pride is hurtn I am not hurt.) So i should of said from the get go in better wording how i was working. Is their a true schematic of the spd that we can look over to see what may of done this? I would disassemble the unit but I want to get a replacement if it was truly defective.
If there was no power connected in or out of the SPD or box, I am not sure why you would feel anything ? There are no power sources inside the SPD itself.
HOWEVER, there is a 1.0 mA (or so) current source circuit in there to light up the blue LED or LEDs. Depending on the SPD model, the center of the LED current source circuit may or may not be connected to the center green GND wire. The LED circuit requires at least 10V input (AC or DC) to work (approximately)
I would need FNG to reply to this too though as he/she/it would know better than I would which version you have.
BUT with NO input or output circuits on, there should not be any voltage source. Are you certain that the AC breakers are good ?
I was hooking up an SPD on my combiner box outside and when I touched the box the LED lit up . That was when I realized something wasn't grounded right somewhere.
Larry
Quote from: ClassicCrazy on April 01, 2020, 07:43:55 PM
I was hooking up an SPD on my combiner box outside and when I touched the box the LED lit up . That was when I realized something wasn't grounded right somewhere.
Larry
If the LED lit up then it had to be that LED current source. That may not require the GND so probably DID come through from the opposite HOT wire. Some SPDs don't draw current for the LED through the GND wire. The reason for that is that some PV grid tie inverters will trip their ground faults when the see any current that is going to GND and not returning through the opposite hot wire.
The current limit is around 1 mA as I remember
At night, my Classic backfeeds power to the combiner box and my SPD LED glows all night
The LED is always lit at my combiner box too - I thought it was supposed to be.
Larry
I just took a SPD300AC off the shelf and confirmed less than 1 mA current flowing from line to ground. That small current illuminates the LED and is enough to cause someone a a mild shock. Current flowing from L1 through to L2 with the ground disconnected was very small and probably would not cause a perceptible shock. Also observed, using a Fluke 111, nearly 120 volts to ground on both the ground wire and on the L2 wire when only L1 is connected to power.
So the OP's observed shock at the generator power inlet cord must have happened because the neutral/ground connection was open.
So this event is a good reminder to turn the power off before working in the panel. I believe that in the E-panel instructions.