Discovered 4 Delta LA 602 DC Lightning Arrestors in my stuff.

softdown

A little research indicates that these are almost made for solar applications. Not as good as the Midnite products....but I have four. What should I do with them? Lightning prone areas warrant four arrestors. This area isn't bad for lightning.

Would imagine that most arrestors are on the AC side of electrical systems.

Each arrestor has two black wires and a single white wire. Sometimes things can be modified to work electrically. Sometimes this is not a great idea.

Mountain Don

Use them and the Midnight ones. They operate on different principles.  Solar expert / guru John Wiles recommends using both;  CYA well.  Direct hits will win regardless. One of our Delta's had the end blown right out of it. I replaced all them and added MN.  Both AC and DC sides. And lots of air terminals, cables, ground rods and plates. I hope we never go through that again. 

mike95490

Midnights cover the low voltage, low power stuff, the Deltas cover much higher voltages and higher power.  2 very different beasts, use both, if you have them

softdown

I don't see how an AC arrestor would differ from a DC arrestor.

Vic

The MidNite SPD use Metal Oxide Varistors.  They can take short duration, and multiple fairly short duration surges.

The Delta units are Arc Gaps,  in a sand quencher.  The Deltas have something like a 7 KV threshold.  Many think that the Deltas are junk.  There are several different models of Deltas,  as is the case with the MN SPDs.

The following IS a Link to a MN Video:

http://midnitesolar.com/video/videoPlay.php?video_ID=85&videoCat_ID=8

AND,  on this page on the MidNite Solar site are a number of videos ...  scroll down to the SPD videos if you are interested this is also a Link:

http://midnitesolar.com/videoDisplay.php

Since you have some Deltas,  why not use them,  while you are installing the correct MN SPDs for your system.

If one has roof mounted PVs  SPDs on the input to and out from the CC would probably be a good idea.

Wind turbines are also good lightning attractors,  so SPDs and possibly Deltas on those leads provably a good idea.

Vic

softdown

Three have: 1 green wire....1 black wire...1 red wire
    One has: 2 black wires....1 white wire

My instincts tell me that maybe it doesn't matter. The principle appears to be that the potted material will absorb and diffuse a moderate spike in energy. It would take a LOT to absorb and diffuse a large, direct hit.

Mountain Don

They should have model numbers.  

Link to Delta on NAWS

softdown

They are all Model LA 602DC. Someone made a mistake with the wiring. I suspect that it doesn't matter. Energy goes to the potted material which can absorb a certain amount of energy.....thats my theory.

EDIT: My mistake. The unit missing the green wire is simply Model LA 602.....so it is an AC unit.

DanS26

About 20 years ago I lost a great deal of equipment to a side strike at my property. 

Since then I have installed numerous SPD's on both the AC and DC side of things. Starting at the transformer a SPD installed by local POCO up on the pole, then a SPD under the meter, then two SPD's in the main distribution panel, a SPD in each of four sub-panels. Now onto the solar system where no less than six SPD's on the AC side and another six on the DC side.

Of the twenty SPD's installed, nine are Midnite models, six are Delta models, the rest a mix. 

I also protect sensitive equipment at point of use.  I don't think you can install too many of these devices. 

softdown

Man...you have of solar gear.