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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Tommy Peel on August 16, 2014, 08:54:47 PM

Title: Interesting/odd forum post...
Post by: Tommy Peel on August 16, 2014, 08:54:47 PM
So my dad's upright freezer quit working a few weeks ago and I was doing some research on trying to repair it and I came across this post:

(http://i.imgur.com/5glI8o7.png)

What are your thoughts on this gentlemen?

Here's a bit more context if it helps:

(http://i.imgur.com/5HSHX5D.png)
Title: Re: Interesting/odd forum post...
Post by: Mark Cadwallader on August 16, 2014, 09:09:57 PM
I suspect (but don't know for sure) that the instruction manual directions are intended to prevent the use of an extension cord or a ground lift ("cheater plug").  Maybe not to prevent those uses, but to avoid liability if/when somebody does either of those things.   Mark C.
Title: Re: Interesting/odd forum post...
Post by: John Roberts {JR} on August 16, 2014, 10:24:38 PM
So my dad's upright freezer quit working a few weeks ago and I was doing some research on trying to repair it and I came across this post:

(http://i.imgur.com/5glI8o7.png)

What are your thoughts on this gentlemen?
If it was a common problem, the freezer manufacturer and power utility would have a duel at dawn to settle the dispute. More likely they would have thrown lawyers at each other.

If it is a common, known problem, the manufacturer would redesign their freezer to survive. Customers always blame the manufacturer first, but with enough incidents the utility has to buy people new freezers. 
Quote
Here's a bit more context if it helps:

(http://i.imgur.com/5HSHX5D.png)

I suspect the power utility would be pretty accommodating about helping you prevent future freezer failures, especially if their distribution was implicated in the problem.

Note: an internet post is not proof that the utility is at fault.

JR
Title: Re: Interesting/odd forum post...
Post by: Mike Sokol on August 17, 2014, 03:41:22 AM
Note: an internet post is not proof that the utility is at fault.

What??? There's something on the Internet that's WRONG?  :o
Title: Re: Interesting/odd forum post...
Post by: Josh Millward on August 18, 2014, 06:52:12 PM
Whole house surge protection is a wonderful thing. I have had it in my current residence and in the previous two.

Obviously you can not say for sure that it saved anything if you don't know there are surge events happening, but I definitely do not generally have trouble with things going bad.

It is a parallel mode brick of MOV's installed on my power panel as close to the meter as possible.
Title: Re: Interesting/odd forum post...
Post by: John Roberts {JR} on August 18, 2014, 07:30:28 PM
Whole house surge protection is a wonderful thing. I have had it in my current residence and in the previous two.

Obviously you can not say for sure that it saved anything if you don't know there are surge events happening, but I definitely do not generally have trouble with things going bad.

It is a parallel mode brick of MOV's installed on my power panel as close to the meter as possible.

I lost one TV set to lightning/surge back when I had cable, since going satellite I haven't lost any appliances. I blame the cable and old TV set design for that melt down.

I do not put much value in anecdotal WWW stories but here's another one.  ;D ;D  I did call MS Power the night my outlets were up to 140V and still climbing.  ???  They did not believe me but came out, confirmed my measurement, then fixed it at their substation, miles from my house.

I guess a whole house surge protector would have got a serious workout from my steady-state constant mains over-voltage.

JR
Title: Re: Interesting/odd forum post...
Post by: Jonathan Johnson on August 18, 2014, 09:43:43 PM
Not applicable to refrigerators (except for the ones with built-in TVs and brains that send you a message on your mobile device to buy milk), but other utilities are often overlooked for surge protection. You can certainly get damaging surges through the TV cable, phone line, and any other copper wire that comes into your house from the outside, including the satellite dish on the roof. With interconnection, surges can travel through these communication lines from device to device killing multiple appliances. A lightning strike hitting the TV cable out on the pole at the street could take out your receiver then propagate through the HDMI cable to your TV, then back to your XBox, through the CAT5 Ethernet to your modem/switch, then to your PC, then fry your iPod that's plugged in the PC's USB port. Better hope you don't have the earbuds in!

Yes, I've seen something similar happen. Multiple components toasted, all in a row. At least there were no earbuds involved.
Title: Re: Interesting/odd forum post...
Post by: Tommy Peel on August 18, 2014, 10:07:26 PM
Not applicable to refrigerators (except for the ones with built-in TVs and brains that send you a message on your mobile device to buy milk), but other utilities are often overlooked for surge protection. You can certainly get damaging surges through the TV cable, phone line, and any other copper wire that comes into your house from the outside, including the satellite dish on the roof. With interconnection, surges can travel through these communication lines from device to device killing multiple appliances. A lightning strike hitting the TV cable out on the pole at the street could take out your receiver then propagate through the HDMI cable to your TV, then back to your XBox, through the CAT5 Ethernet to your modem/switch, then to your PC, then fry your iPod that's plugged in the PC's USB port. Better hope you don't have the earbuds in!

Yes, I've seen something similar happen. Multiple components toasted, all in a row. At least there were no earbuds involved.
To chase this rabbit a little bit, what kind of surge protector would help this situation if any? I know they make them with coaxial in/out and phone in/out.

Sent from my Moto X (XT1053) using Tapatalk

Title: Re: Interesting/odd forum post...
Post by: Jonathan Johnson on August 18, 2014, 10:44:25 PM
To chase this rabbit a little bit, what kind of surge protector would help this situation if any? I know they make them with coaxial in/out and phone in/out.
The few coax/phone protectors I've seen have far lower joule ratings than for the power lines, as though they are an afterthought. What I'm curious about is if anyone makes one for a balanced audio signal (XLR in/out). That could be useful when you have an audio feed to another building on campus, or are feeding to a TV truck that's on a different power source, or even for the outdoor festival that has to shut down due to weather. What's to protect FOH from a strike to the stage roof structure*? I just not convinced an isolation transformer is going to be much help here!

* I know, a digital snake connected by fiber.
Title: Re: Interesting/odd forum post...
Post by: Chris Hindle on August 19, 2014, 09:07:56 AM
* I know, a digital snake connected by fiber.
Well, if you already know the answer....... :D
Title: Re: Interesting/odd forum post...
Post by: Stephen Swaffer on August 19, 2014, 04:49:19 PM
Years ago we used fast acting fuses on 66 punch down blocks to protect electronic phones in different buildings. Theyy seemed to be very effective significantly reducing the number of damaged phones/KSUs.

Fuses have a much higher interrupting rating than breakers as well as they can act many times faster.  They are an effective way of reducing the hazards and damage caused by arc flash.

 I have often wondered if fuses-perhaps even with MOVs after them to short high fault voltages to ground and thus blow the fuses wouldn't be an effective protection against catastrophic surges? Low amp very fast acting could be used on signal circuits. Obviously blown fuses are less convenient and take longer to recover from during a show than blown breakers, but they would be faster to recover from than blown gear.
Title: Re: Interesting/odd forum post...
Post by: Scott Helmke on August 20, 2014, 06:09:58 PM
I've had it happen in two different offices - nearby lighting strike causes minimal damage through the power lines, but manages to induce enough voltage on the network and phone lines *between* things to cause a lot of damage. Had to replace a bunch of network cards, etc.
Title: Re: Interesting/odd forum post...
Post by: Mike Sokol on August 20, 2014, 07:08:21 PM
I've had it happen in two different offices - nearby lighting strike causes minimal damage through the power lines, but manages to induce enough voltage on the network and phone lines *between* things to cause a lot of damage. Had to replace a bunch of network cards, etc.

Can we move this over to the SurgeX LED Talk thread? Might get some insight from Martin at SurgeX.