Other MidNite Electronics > MidNite SPD (Lightning arrestor)

Spd300 ac sends volts thru from ac out to ac in?

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The Ugly One:
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.

The Ugly One

The Manual:


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.


The Ugly One:
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.


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