classic light in a faraday cage, how much air space is needed

[jim k.]

I'm ordering a classic light today with a spd and I have a alum. box which is 2'x3'x1' which I want to install the cc and a series of 15 amp circuit breakers in, will I need some type of protected venting for cooling air.

[Volvo Farmer]

Doesn't mesh screen act as a faraday cage? That would seem to solve any cooling issues.

[TomW]

Doesn't mesh screen act as a faraday cage? That would seem to solve any cooling issues.

VF;

Exactly what I thought when I first read this.

Tom

[boB]

The smaller the mesh grid size, the higher the frequency the cage will tend to shield.

But of course the worse it will let things cool.

The larger the overall shield size, the better the cooling as well.
It's kind of like placing the Classic in a large room vs. a very small box.

boB

[jim k.]

good answers, I am putting this right down under the pv s exposed to weather but I have some fine mesh stainless screen, I'll put some big vents in it, thanks alot.

[niel]

another important venting aspect you will see is that for draining out condensation on the bottom of the enclosure. it is important that this does not build up into a pool of water that could harm your stuff.

[Volvo Farmer]

Why do you want to put a faraday cage around a charge controller? Are you trying to keep something out or in?

[jim k.]

If you look at what happened to the electronics in Alaska during last yrs solar flares this is why, A large  flare will knock them out, sometimes temp. and sometimes permanent.  All the aircraft lost there nav systems.

[niel]

hmm. i made an assumption that this might be outside, but in retrospect i have to ask if it will be inside? if inside then the condensation is most likely to be less of a problem. for the purposes of a faraday cage, you could have some good sized holes in the box's casing and still have good integrity against flares. your big problem won't be that it gets through the casing of the classic, but would most likely make its way in via the wiring. remember the classic casing is metal too.

if you fear the flares then encase the wires in metal conduit, properly ground everything, and use spds. during an event turn the disconnect to the pvs off making sure that there will still be an active spd on the input to the classic. be sure the spd is on the battery side of the dc electronics as well just in case it should be picked up on the dc wiring too. of course the ac side of things too, be it an inverter or the grid, should also have spd protections. as like with shutting down the pvs during a strong flare, you can also shut down all other circuits ac and dc alike. that especially holds true of the grid as that is one big pickup wire.

imho, you don't need the outer box casing to go around the classic as it's the wires you need to address. by itself with nothing connected to it the classic will be fine.

[jim k.]

this is totally  of grid with no cross connect what so ever, today on ups I should have a new classic and two spd's arriving, I am not very concerned about "emp"s in our area, but we do have quite a bit of lightening from time to time, one such strike on the hill above us about 1/4 mile away knocked out  the Lnb on our sat dish so this is the type of thing I'm trying to prevent, also the electonics, batteries the whole pkg of stuff is going to be right under the frame work the panels are mounted on with a feed in conduit going to a ac sub panel on the back porch,  maybe a little to much time on my hands overthinking the whole thing.

[boB]

this is totally  of grid with no cross connect what so ever, today on ups I should have a new classic and two spd's arriving, I am not very concerned about "emp"s in our area, but we do have quite a bit of lightening from time to time, one such strike on the hill above us about 1/4 mile away knocked out  the Lnb on our sat dish so this is the type of thing I'm trying to prevent, also the electonics, batteries the whole pkg of stuff is going to be right under the frame work the panels are mounted on with a feed in conduit going to a ac sub panel on the back porch,  maybe a little to much time on my hands overthinking the whole thing.

I assumed you wanted a Faraday shield for EMI reduction.

I don't think you need a Faraday shield so much...  You really do need an SPD300 or two
for the lightning.

boB

[TomW]

If sky sparks are your main concern you absolutely need a protection device on every cable coming in to the electronics. While possible, it is fairly unlikely the electronics themselves will be directly affected by a lightning induced pulse. It invariably gets in on cables. In many locations those drive in copper coated ground rods are insufficient for a good solid ground. I buried #6 bare copper in my trenches to the house and my arrays along with the conduit for the power cables. I have issues here with lightning even with protective devices more than likely caused by the dry soil not giving good grounds thru ground rods. So I buried about 100 feet of copper in my trenches to ensure I have solid earth grounds in place. All the RE equipment is in my office in the garage across 100 feet of driveway and I just upgraded the AC feed and phone / internet cabling to the house as well as a set of cables to the new solar array location which is not installed but on the schedule. I buried ground wires in both trenches so I hope my grounding worries are over.

Good luck with your project and avoiding damage from thunderbolts.

Tom