# Working with Power



## the_rookie (Sep 30, 2008)

Didn't know how exactly to name the thread, but I was wondering is there a way I can get a new cable for my Onkyo 876. I want one with a grounded plug. Is it possible? I was thinking it might be beneficial to get one for it.

Secondly, anyone know any good surge protectors? I am running a older panamax max6. Do i need an upgrade or is this good enough for a 1080p plasma, onkyo 876, and many gaming consoles?


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## mechman (Feb 8, 2007)

Have you checked with Onkyo?


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## brucek (Apr 11, 2006)

> I want one with a grounded plug. Is it possible? I was thinking it might be beneficial to get one for it.


Did it come with a two prong plug as standard equipment?

brucek


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## Anthony (Oct 5, 2006)

Depending on the type of surge suppressor, it may be due for a replacement. MOV type surge protectors have a usage life. Anywhere from 3 to 7 years, depending on how many surges (and how bad) they stop. The MOV element breaks down over time after every hit.

Some higher end protectors have an LED circuit that monitors the life and turns on (or turns off) when it's done. My whole-house surge suppressor has this. If the green light is on, it's still good. Check the manual to see if there are any recommendations as to life expentency, or indicators as to when it's "had enough" 

There are other types of surge suppressors that don't wear out over time (Brickwall brand comes to mind), but the Panamax is likely an MOV.

As to the power plug: what are you hoping to gain from doing that? Do you want to make sure the chassis is grounded for safety? Do you have a hum in your system? There are other ways to fix those without rewiring the power supply.


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## the_rookie (Sep 30, 2008)

I don't think i have ever encountered a surge. I have had it for around 10 years, and i have about 3 of them. All 3 still have the light saying its protected.

As for the cable;
i havent contacted Onkyo. 
Yes it is a standard 2 prong
I was thinking it would be better overall. I was just under the impression it would give multiple benefits to have it grounded, not only to counter a hum, but protect it. It doesn't have a hum, but in the future something may cause it to. I was thinking of cutting it off at the pass, and stopping it now before I encounter it


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## tonyvdb (Sep 5, 2007)

If you look closely at the part where the power cable plugs in to the back of the receiver you will notice that it only has two contacts so adding a grounded cable will not help at all as the ground would not connect to anything. That said you could if you think your having issues run a ground wire from any unpainted screw on the receiver to the screw that holds the cover plate on to the plug in as this (if wired properly) is also grounded.

As far as a surge protector is concerned dont spend too much money on a replacement Triplite make really good ones that wont break the bank and some even have noise filters like these ones here. They are used alot in hospitals.


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## brucek (Apr 11, 2006)

tonyvdb said:


> That said you could if you think your having issues run a ground wire from any unpainted screw on the receiver to the screw that holds the cover plate on to the plug in as this (if wired properly) is also grounded.


A device with a standard two prong plug has a double insulated chassis and is meant to operate with a two prong plug. In fact, these chassis types must not have an ground conductor attached to them, as this could render them unsafe. Double insulated devices should only use a two-pin plug.

brucek


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## lcaillo (May 2, 2006)

You should never connect a ground to any point inside the unit, but there should never be a problem connecting any metal part on the outside of a unit to ground. A unit with a two prong plug must, by design, not have more than 500uA of leakage current on any exposed part, and dropping that to ground potential should be no problem. It should not be needed, but it should be no problem.

The idea that MOVs "wear out" is often misunderstood. They do break down with many large surges, but in most cases, they last a lifetime. When they do break down, they almost always fail as a short, so you will know if they are not functioning. If that ever happens and you have a Panamax, Tripplite or one of the better brands, they will usually just replace them as those brands have lifetime warranties on many of their products. Better quality units like the Panamax actually have multiple MOVs so you are not relying on only one device. If any of them fail, you will have a dead short and your breaker will open.

Series mode units are fine, but one must be aware that many problems come over signal lines and their grounds, so failure to protect those lines or to ground them properly can compromise protection. Most series mode units do not have protection for signal lines.


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## robbo266317 (Sep 22, 2008)

I have a Pioneer receiver and it is double insulated and only has a two prong 240v plug. 
One of the case screws has an area of unpainted metal around it and an earth symbol beside it.


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## Anthony (Oct 5, 2006)

That's what I was going to recommend if grounding was the only reason for doing this. Many components and power strips have a "grounding lug" that you can daisy chain a wire to, effectively giving all the cases a common ground through the power distro unit. I've never used this, but I know my Panamax has one of these as does my receiver.


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## lcaillo (May 2, 2006)

A "daisy chain" or other chain or link method of grounding is inferior to single point grounding. Ideally everything should be grounded to the same point if you have multiple grounds. In all but the rarest cases, additional grounding beyond that intended by the design of the component is not necessary if the system is installed properly. In thirty years of installation and service, I cannot recall ever having to add a ground to any component, other than correcting installations that were not done properly.


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## Anthony (Oct 5, 2006)

Agreed. I don't use the feature on mine, but when I got a ground loop hum once, I thought about trying it. Grounding the cable distro block outside fixed it, so there was no need to link the components inside.


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## lcaillo (May 2, 2006)

Far more important than any grounds between component chassis are the connections outside like you describe Anthony. What most people never realize is that the ground on the electrical service is often buried and can corrode and get loose with time. I check mine and clean the connections and tighten them every year or two. I recently has noise on my phone line and found a bad ground connection from the phone line at the entry point to the house. A little DeOxit is magic...


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## Strype (Feb 17, 2009)

lcaillo said:


> Far more important than any grounds between component chassis are the connections outside like you describe Anthony. What most people never realize is that the ground on the electrical service is often buried and can corrode and get loose with time. I check mine and clean the connections and tighten them every year or two. I recently has noise on my phone line and found a bad ground connection from the phone line at the entry point to the house. A little DeOxit is magic...


good advice


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