SPST or DPST power switch? - Page 2 - 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 16th August 2014, 07:40 PM   #11
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
From the 2014 ARRL Handbook:
Attached Images
File Type: jpg ARRL_Gnd2.jpg (169.1 KB, 70 views)
  Reply With Quote
Old 16th August 2014, 07:46 PM   #12
diyAudio Member
 
Join Date: Nov 2008
Location: Oakmont PA
Quote:
Originally Posted by jackinnj View Post
From the 2014 ARRL Handbook:
Absolutely right. I am aware of two electricians that were killed because they thought they had switched off a circuit. A DPDT switch can short on the hot side and give the indication of being off when the circuit is still dangerous.
  Reply With Quote
Old 17th August 2014, 01:02 PM   #13
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Might want to pass that along to the folks at Elektor and AudioXpress.
  Reply With Quote
Old 17th August 2014, 02:50 PM   #14
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
It may be that what the ARRL meant to say is that a switch/fuse should not be placed in the neutral line alone. Or maybe it can be guaranteed that no US installation ever has live and neutral swapped, or a fault which raises the potential of neutral?

Last edited by DF96; 17th August 2014 at 02:51 PM. Reason: extend
  Reply With Quote
Old 17th August 2014, 04:40 PM   #15
diyAudio Member
 
Speedskater's Avatar
 
Join Date: Sep 2002
Location: Lakewood, Ohio
Really it should mean an independent switch or fuse. A dual linked switch or circuit breaker would be OK. Don't think that we have any dual linked fuses handy.
__________________
Kevin
  Reply With Quote
Old 18th August 2014, 02:03 AM   #16
diyAudio Member
 
Join Date: Jan 2014
Location: NYC, New York, USA
Quote:
Originally Posted by jackinnj View Post
From the 2014 ARRL Handbook:
My understanding is that this refers to breakers or fuses for the main house wiring, not for appliances, and, indeed, the code prohibits this.

Generator transfer panels must switch both hot and neutral, for obvious reasons.

I have seen numbers ranging from 0.5-2% for miswired home electrical circuits in the US. My personal experience—based upon the small sample size of every apartment I've lived or those for my friends—is that at least one miswired outlet is always present. My current apartment had 2 out of 11 outlets miswired, about 20%.

BUT, then again, my friends and I live in old buildings with antediluvian electrical systems because we're not rich, so YMMV. I'm sure newer buildings are wired better. Although when my parents had their kitchen renovated the electrical inspector did NOT check the wiring. It was all perfect, but that's not the point; the inspector simply did not check.
  Reply With Quote
Old 18th August 2014, 08:15 AM   #17
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by Retrovert View Post
................... My current apartment had 2 out of 11 outlets ....................I live in old buildings with antediluvian electrical systems ................
My Lounge has 8 double socket outlet plus 3 socket outlets for table lamps. Even the kitchen has 6 double socket outlets.
The whole 4bedroom house (~200m²) has ~90 power sockets.

All have been checked during construction and rechecked by me using that simple and cheap plug in tester.
0% miswired.

And I still use double pole mains switching in my equipment, when switching is included. Some have an IEC inlet socket in lieu of a mains switch.
__________________
regards Andrew T.

Last edited by AndrewT; 18th August 2014 at 08:18 AM.
  Reply With Quote
Old 18th August 2014, 01:13 PM   #18
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally Posted by Retrovert View Post
antediluvian electrical systems
Anything pre-Tropical Storm Sandy is, by definition "antediluvian" -- at least south of 23rd St.
  Reply With Quote
Old 19th August 2014, 08:42 AM   #19
Almeg69 is offline Almeg69  United Kingdom
diyAudio Member
 
Join Date: Mar 2009
As I run a balanced mains transformer, I will always use a double pole switch on my projects.
__________________
Alex H
  Reply With Quote
Old 19th August 2014, 10:01 AM   #20
freax is offline freax  Australia
diyAudio Member
 
freax's Avatar
 
Join Date: Sep 2007
Location: NSW
Now... As a fan of Edison I'm using nothing but 12v/24v DC, so what is the story there?

The neutral of my battery bank is earthed so I could safely use SPST throughout however in the event of high voltage coming into contact with either my solar panel system/loads/battery bank I would need to leave Negative connected so the case of my projects don't become live. Correct?

The solar panel is supposed to be earthed. as part of Australian design code.
The battery bank must be earthed on the negative. as part of code.
There must be a breaker on the solar panels and on the battery bank from the load.
And all wiring must be run through "heavy duty conduit", i'm assuming that means metal conduit.
And of course signs setup for emergency personell's safety.

I may have to run a third earth wire for all loads? That way it shouldn't matter if I use SPST and disconnect positive only or use DPDT and disconnect both positive and negative at the same time.

If all else fails take the safest route. DPDT throughout with a dedicated earth wire.

Please note, I'm talking about a low voltage 12/24v DC system here.

As for fusing, I'm thinking of just fusing the positive side as usual.
__________________
"It seems that perfection is reached not when there is nothing left to add, but when there is nothing left to take away" - Antoine de Saint Exupéry

Last edited by freax; 19th August 2014 at 10:12 AM.
  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
circuit to switch LEDs and relays with an SPST tadakan Construction Tips 4 1st June 2012 06:46 PM
HELP - looking for round DPST or DPDT rocker switch CharlieLaub Parts 8 26th September 2011 03:34 AM
Help needed finding a small DPST switch - confused! Horsebox Tubes / Valves 15 30th March 2011 05:23 AM
Wiring SPST Switch with Neon Lamp PhrazeMaster Construction Tips 5 9th January 2011 08:28 PM
Quad SPST Analog Switch RCruz Solid State 7 25th November 2008 12:07 PM


New To Site? Need Help?

All times are GMT. The time now is 06:23 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