Simple AC line filter on a power strip

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Studiogearlover

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Joined
Mar 14, 2017
Messages
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hello and I hope you are all safe and sound...

I would like to hear your opinion installing a simple AC line filter ( a simple 100nf cap) into a power strip. I have this (attached) and just out of curiosity I opened it. It has a circuit breaker , a switch and 8 individual sockets. Interestingly as seen on the pic the wires at the end of the last socket just been chopped off and left like that. I am wondering is it a good place there to put a 100nf MKT cap? 

Is it worth it at all? Some say you need to put 100nf caps on each individual sockets...?

If any of you have done anything similar or tested this, would like to hear your input or opinion :)

Many thanks for your suggestions in advance...
 

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Studiogearlover said:
hello and I hope you are all safe and sound...

I would like to hear your opinion installing a simple AC line filter ( a simple 100nf cap) into a power strip. I have this (attached) and just out of curiosity I opened it. It has a circuit breaker , a switch and 8 individual sockets. Interestingly as seen on the pic the wires at the end of the last socket just been chopped off and left like that. I am wondering is it a good place there to put a 100nf MKT cap? 

Is it worth it at all? Some say you need to put 100nf caps on each individual sockets...?

If any of you have done anything similar or tested this, would like to hear your input or opinion :)

Many thanks for your suggestions in advance...
You should put specific capacitors there. They're called class-X. Most modern gear already has X and Y capacitors, so adding them to a power strip may not do much.
Y capacitors are connected between Line and Earth and between Neutral and Earth, for protection against common-mode EMI.
X type are between Live and Neutral and protect against differential mode EMI.
 
+1 one only use capacitors designed specifically for that application, to avoid dangerous failure modes. These capacitors use specific technology with benign failure modes, because all components fail.

Another common problem with cheap power strips is the standard over voltage suppression devices can get leaky over time and dump leakage current into safety ground. I encountered a weird issue in my old house that lacks 3 circuit outlet wiring. I was using one of those rogue outlet strips for several kitchen appliances. The current leaking into the floating safety ground energized the chassis ground of my kitchenaid mixer. It was not enough current to be dangerous but it was enough that I could feel it. I have since run a safety ground wire to the outlet in my kitchen by the sink and one in my laundry room, that the dishwasher and washing machine plugs into. I also use GFCI outlets for any mains power near water.

JR

PS: For too much info I got shocks in my shower from my hot water heater when it rusted through the heater box and energized the hot water, now that's hot water. The replacement water heater and copper plumbing is now ground bonded. 

 
Thank you guys for the suggestions. I really appreciate your thoughts. I think I will leave it for no, wont touch the socket. The gear I was about to plug into all of them has a filter cap at the AC line... shouldve check that first.

:)
 
High quality industrial filters can be found pretty cheap sometimes.

I've got one of these;

https://www.stockclear.nl/a-54875856/ontstoorfilters/delta-emi-filter-20a-100-250v/#description

 
scott2000 said:
If suspecting goofy noise issues from something like a cheap Furman "power conditioner" would it be bad practice to remove any MOVs? Or would looking to replace them be recommended?
MOV's regularly fail, most of the times going open-circuit, as if not there anymore, and there's no easy way to know. It often happens that one discovers they are shot by seen them charred.
Good practice says replace them, however in some cases they fail so often that one gives up.
 
Good practice says replace them, however in some cases they fail so often that one gives up.

???

"As a result, designers who expect to make the transition to IEC 62368-1 should plan to spend some time trying to understand how to comply with the MOV requirements, and should be prepared for possible differing interpretations among safety experts and test labs."

"At present, most designers of information technology equipment (ITE) have the option of using national

standards that are based on the 2013 version of IEC 60950-1, or alternate national standards that are based on either the 2014 or 2018 versions of IEC 62368-1. However, at some point in the future, most national standards based on IEC 60950-1 will be withdrawn, and the only applicable standards for ITE will be based on IEC 62368-1. In the EU and the U.S., the withdrawal of EN 60950-1 is presently scheduled for December 2020."

https://incompliancemag.com/article/new-requirements-for-movs-used-for-surge-suppression-on-ac-mains-ports/


I guess those SurgeX, Brick wall , zerosurge things look pretty ok?


 
"those SurgeX, Brick wall , zerosurge things" are very good and very pricey!
A better plan might be a modern whole home unit at the service entrance/main breaker panel. (some will even text you if they have a problem)
MOV's have come a long way in the last half century. Some of the bad reports are now decades old.
 

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