CurtPalme.com Home Theater Forum

Cube · Joined: 06 Dec 2009 Posts: 77 Location: IL, USA

I took down an old Runco (Zenith 851) that had been installed by a home theater installer in the early 90s. Planning to put up a Sony 1272 in its place.

The projector was plugged into an outlet on a private circuit coming from the breaker, but I noticed they used a ground adapter to defeat the grounding prong on the projector's power cord (to prevent loops?). I don't have whole-house surge protection other than the breaker, but the Runco did have its own replaceable fuse on the power supply (which has never blown). The "new" 1272 doesn't.

Would it better to plug the 1272 into an ordinary MOV power strip or just plug it directly into the outlet? I'm not thrilled with the thought of having a MOV hidden above a suspended ceiling. Or am I stupid not to get a whole-house surge protector?

emdawgz1 · Joined: 14 Mar 2006 Posts: 7949

Panamax makes in wall surge protection.

http://www.panamax.com/Products/In-Wall/Default.aspx

betel · Posted: Tue May 18, 2010 9:21 pm Post subject:

The problem with local surge protectors is they have to absorb the excess energy which really limits their protection ability. Whereas a whole house surge protector shunts the excess energy to ground before it enters your home. I recently installed a whole house surge protector by Intermatic (IG3240RC). It was about $150. IMO local surge protectors are a waste of money.

kschmit2 · Posted: Wed May 19, 2010 12:45 pm Post subject:

I use Belkin PureAV Power Consoles

**AnalogRocks**

WanMan · Joined: 19 Mar 2006 Posts: 10270

emdawgz1 · Joined: 14 Mar 2006 Posts: 7949

**Curt Palme** · Posted: Wed May 19, 2010 6:04 pm Post subject:

Two points on this:

-if you have generally clean power like we do here in Vancouver (maybe 3 blackouts a year for a short period of time), then there's really no need for a surge protector, small, big or otherwise. THe hype by the 'plug your stuff into this and it will never fail' companies is ridiculous.

-if you do have surges or frequent lightning hits, then a whole house protector is the way to go.

Keep in mind though that you can protect your AC wiring all you want, but if lightning strikes a telephone pole outside, your AC _might_ be protected (usually not if the strike is very close to your house, the surge protector won't be big enough to absorb the power), but your cable, satellite and telephone lines won't be, and a surge through your cable can blow your TV and cable box and/or anything else.

Best bet if you know a storm is coming is to unplug the cable/satellite and AC cords.

betel · Posted: Wed May 19, 2010 8:03 pm Post subject:

stefuel · Posted: Wed May 19, 2010 10:51 pm Post subject:

I like my solution very much. I have a giant APC rack mount UPS in my theater equipment rack. Everything associated with the theater including the projector which is 50 feet away from the rack is plugged into it. It has "Smart Boost" and "Smart Trim" which means it monitors the incoming voltage and kicks in if there's about a .04 percent variation in line voltage. It also communicates via RS-232 to my Crestron system to trigger a safe shut-down of my system in the event of a total power failure. The theater will stay running for 7 minutes if the power does not come right back on. The power has gone out many times since I installed it for less than 7 minutes and I never knew it if I was watching a movie. The only indication that there is a power problem in the theater is a pop-up screen on the control touch panel that says "POWER" along with a count down timer.

David_Web · Joined: 02 May 2007 Posts: 418 Location: Sweden

UPS is nice, however not nice to break. Eats a little electricity in the mean time though but it's worth it.

I'm thinking of DIYing that brickwall filter.
Got to find a simple way to keep "bias" running around 2V over peak voltage. Not happy with the resulting ripple current otherwise.
Then follow line voltage as it changes, which it does a lot.

A simple sim shows initial great results though.

Should even have some suitable inductors laying around.

westom · Joined: 14 Dec 2009 Posts: 56

David_Web · Joined: 02 May 2007 Posts: 418 Location: Sweden

That last link is scary. Thankfully I live in Sweden where this sort of thing would result in prison or heavy fines.

I have a few MOV protecting most electrical equipment. Ill have to check so if it catches fire it won't burn down the house.
Putting a fuse before the MOV is not a bas idea. It's only for "last resort" anyway.
Every substation have real lighting tubes that take any hit. And a direct hit after it should not happen as everything is under ground.
The gas-filled tubes only have a limited life though so I hope they look after them.

My biggest worry is phone line as it has high enough resistance to get hit anywhere. Thankfully ADSL filter took the biggest hit.
Thinking of putting some sort of MOV or other clamp where it enters the house, then have two thin wires before it that can burn off if it hits.
I don't really want to burn the incoming lines.

Between network equipment I have put a bunch of surge protectors, I had them already and no dropped packets yet so why not.
A mix of old UPS and addons that had network protection, thing most of them use diodes I think.
Last time I was a hit on the pone lines the surge traveled through the LAN taking out a few things. The switch lost a few ports, modem and router went and Squeezebox lost it's wired network. Good thing wireless still works.
The ADSL splitter had evaporated the traces in the PCB so it took the most amps and probably saved most of the other equipment.
Electrical was protected by the substation as we only lost power for a few minutes, no other equipment was hurt. Not even CFL that usually dies if you look at it wrong.

westom · Joined: 14 Dec 2009 Posts: 56

Cube · Joined: 06 Dec 2009 Posts: 77 Location: IL, USA

Forgive me for being obtuse, but what exactly is the best thing to do then? Avoid MOV strips entirely and make sure all the wiring coming into the house is grounded effectively at the breaker box?

Also, what's the deal with these expensive "series-type" surge protectors?

westom · Joined: 14 Dec 2009 Posts: 56

David_Web · Joined: 02 May 2007 Posts: 418 Location: Sweden

Most low voltage distribution is done under ground unless you are way outside a city, and even then it isn't that bad.
I'm not sure how the grounding is done in this house, but lightning won't really hit anything after the last substation. And before that there is usually a bigger substation before it goes in the air.

I am not trying to protect from a direct hit as it really won't happen, and if it does the lighting bolt is already in the house and it's game over.
I am trying to protect equipment from burning out due to a transient caused by lightning (which is pretty much the only thing causing them here).

I am pretty sure the power into the house did not flinch that hit, and the first device in (ADSL splitter) had burned(evaporated) traces where the two cables comes in. It is possible that it found ground through the modems wallwart or similar.

Network equipment usually uses an isolation transformer meaning no ground between them, you only have to worry about differential voltage on each pair. (unless you use a cable with ground and the equipment supports it)
Not sure if the cheaper modem and switch that died did though. Have to check.

100m phone line gets you around 17ohm or so, is that not high resistance compared to power lines?
Impedance will only be higher, although not that much as the lines are good for ADSL speeds.

SPICE simulation of a brickwall type filter (series mode) shows good results against short transients.
1000V lands around 110A through the second 180uF stage.
The coils actually drops all 1kV of the hit at first but then climbs to 100V above normal voltage.
100kW is dumped across the coil and 36kW into the capacitor.

Obviously this is only first simulations but it shows potential to stop otherwise harmful surges.

Will it stop a direct lightning hit? No. That simply won't happen. You can't capture or absorb lightning, you can only hope to divert it to ground.

I will read the links later. It's late here if the post seems slight disoriented =)

westom · Joined: 14 Dec 2009 Posts: 56

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Alright.................... I said this before and I'll say it again......and I think Curt said it here somewhere.............................There is only ONE way to protect your equipment from a lightning strike whether its at your house or down the road some miles.

UNPLUG IT

Surge protection is for minor variations in the normal flow of electricity into your home.

David_Web · Joined: 02 May 2007 Posts: 418 Location: Sweden

And the times you can't unplug?
I do try to unplug most things but you can't unplug fridge etc.

Ill have too look over the ground. Maybe add one if needed. Can't hurt.
Otherwise the electrical should be fine as no dimmers or other equipment is broken yet.
That rebar/concrete method looks easy to do. Just use a grid meant for concrete reinforcement and connect it to ground. (after digging it down).
Code requires that any conductive reinforcement of concrete is connected to ground anyway.

How about the phone line?
I think it enters at another location, what is the most effective way to deal with that?
That is obviously the weak point right now.
Could possibly make a separate ground for it right outside if needed. Have to look it up.

I am thinking of adding a fiber link between the modem and router as I happen to have one, a little last resort paranoia maybe.