Final verification of Protective Earth wiring - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 4th July 2011, 03:22 PM   #1
diyAudio Member
 
Join Date: Sep 2010
Default Final verification of Protective Earth wiring

Hello,

I am finally ready to wire up my big amp project. It's grown from what I originally intended, but that's alright. There are 5 parts essentially. one left and right channel board, one subwoofer board, one subwoofer preamp board, one headphone amp, and one fan. There are two transformers. A 25/25VAC torroid and a 6V-0-6V center tapped trafo.

That's what I need to wire. The biggest "problem" is that I am in a WOODEN chassis. I've attached a diagram on how I think I would wire it up going off what I have learned.

The main concern is, "Did I wire protective earth correctly?". Of course the IEC would be fused, and switched, but for simplicity's sake, I'm leaving it like that.

Click the image to open in full size.

Thanks.
Attached Images
File Type: png Wiring.png (91.1 KB, 157 views)

Last edited by TheLaw117; 4th July 2011 at 03:50 PM.
  Reply With Quote
Old 4th July 2011, 04:26 PM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi, technically I can't fault what you have shown, but I hate it because it gives the impression that you have put a CL60 in the PE route.

You and anyone reading your diagram must realise that the PE (in your system) is the earth tag on the IEC socket. Everything else after the CL60 is PSU zero Volts and/or Main Audio Ground. These parts are NOT part of the PE system.

If you agree then it would be wise to label your diagram accordingly.

Next:
Have you connected all exposed conductive parts to Safety Earth?
Is the IEC socket enclosure connected to PE (it is probably soldered but worth checking.
Do you consider it necessary to "earth" the small EI frame?
Will a mains fault route that touches any internal parts survive long enough to rupture the mains fuse and allow time for the arc to extinguish? This route may have to pass in excess of 1kA.
__________________
regards Andrew T.
  Reply With Quote
Old 4th July 2011, 04:29 PM   #3
Boofers is offline Boofers  Canada
diyAudio Member
 
Join Date: Oct 2008
Location: Ontario
Blog Entries: 1
Great drawing! Looks good. Where you've separated the earth and circuit grounds with the CL-60, I have also seen other components in parallel in that location. A 0.1uF capacitor will short high frequency (RF) signals to ground. A diode from earth to circuit and another diode from circuit to earth act as a protective circuit in case of a major problem.Power Supply for Power Amplifiers
  Reply With Quote
Old 4th July 2011, 05:10 PM   #4
diyAudio Member
 
Join Date: Sep 2010
Thanks everyone.

Andrew,

I know I've asked this many times, but in a wooden case like this, PE is not connecting up to the 0V/Ground at all?

This is a picture from a thread called "Yuanjing" Gainclone 3886...this board is one of the boards I'm using. Notice how PE was connected here. This is incorrect?

Click the image to open in full size.

So where does CL-60 go?

Thanks.

Boofers,

Thanks. I'll definitley look at that. Westhost/ESP is a great site.
  Reply With Quote
Old 4th July 2011, 05:16 PM   #5
diyAudio Member
 
Join Date: Sep 2010
The way the IEC filter is made, the PE solder tab is actually part of the metal frame of the filter. So it's technically hooked up to PE.
  Reply With Quote
Old 4th July 2011, 06:01 PM   #6
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Post 4 shows the PE directly connected to chassis. This is correct. OOPS, I had a closer look. That seems to be a soldered joint. That is not adequate.

Post1 shows a green wire from PE to small transformer Zero Volts terminal via, CL60 and via toroid Zero Volts. Since these are all the same colour, your description and the drawing give the mistaken impression that all the GRN wires are PE.

The PE is only the 1/4" spade. The IEC socket casing is electrically connected via a soldered joint. Theoretically since this is not a mechanical joint this is technically not part of the Safety Earth. However in practice that solder joint is unlikely to ever melt and thus the socket casing is effectively directly connected to the PE.

The green wires are not the PE. The Green wires are PSU Zero Volts.
__________________
regards Andrew T.
  Reply With Quote
Old 4th July 2011, 09:14 PM   #7
diyAudio Member
 
Join Date: Sep 2010
Alright. I think I understand. So everything from the IEC to the CL-60 is protective earth, whilst everything after that is 0V/Return/Ground?

What is your opinion about using the ESP method? 2 diodes, 10R resistor, and a 100nF cap? VS using a CL-60? I have a CL-60, and I probably have the components for the ESP method....

So, is there a "better" one?

Thank you very much.
  Reply With Quote
Old 5th July 2011, 08:48 AM   #8
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
The "ESP method" appears to have been copied from this Forum. It was a new addition to his site after we had been discussing it for some months. It was nice to see that Rod could sift the wheat from the chaff and do an accurate paper on "how to". EXCEPT, the diagram shows PE going to the rectifier instead of the chassis.

I have only ever tested the big bridge rectifier//small ceramic//small resistor. It passed without any "apparent" damage. Judging by the condition of the fuseholder and the fuses, or what I could find of them, after the explosion, it was a mighty test.

You or someone else would need to repeat that test to get the comparison you are asking for.
__________________
regards Andrew T.
  Reply With Quote
Old 5th July 2011, 04:49 PM   #9
diyAudio Member
 
Join Date: Sep 2010
I think I'll just use the CL-60, since it's a "proven" method. Otherwise, the wiring is alright?

So since I am using a wooden case...

Wire from IEC PE -> Bolt -> Wire to CL-60 -> Wire to Screw terminal -> Wire to all audio/power ground

Thanks.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
GND/Earth Wiring Management by Power Amplifiers - what is the royal Way tiefbassuebertr Solid State 11 3rd January 2013 09:46 AM
Tone arm earth wiring and DIN plug questions. tubenut Analogue Source 8 14th August 2005 05:51 PM


New To Site? Need Help?

All times are GMT. The time now is 08:08 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2