ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Violation?
by renosteinke - 01/27/23 09:52 PM
Does NEC 551.71 (F) apply to dwellings?
by BigB - 01/20/23 10:46 AM
Power submeter connections
by HotLine1 - 01/19/23 09:09 AM
AFDD's coming to the UK
by Texas_Ranger - 01/17/23 07:22 PM
New in the Gallery:
Burger King crown sillyness
Burger King crown sillyness
by wa2ise, December 11
240/208 to a house
240/208 to a house
by wa2ise, October 9
Who's Online Now
0 members (), 27 guests, and 12 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#113054 02/19/02 12:20 AM
Joined: Oct 2000
Posts: 3,672
Likes: 2
Admin Offline OP
Administrator
Member
[Linked Image]

[Linked Image]

[Linked Image]
Quote
This was found at the rear of some public address equipment that was located in an industrial setting in the Los Angeles area. The line cord runs from the plugmold to the fuse mounted on the rack panel. This is completely in the open, not even so much as a closed rack cabinet! It's also mixed in
with low voltage, and speaker/mic audio lines. It was reported to the technical experts at the site -- now we'll see if they fix it before there is an accident!!

Anomyous

#113055 02/19/02 12:15 PM
Joined: Nov 2001
Posts: 745
M
Member
Even assuming that this rack is located in an area accessible only to qualified personnel, this equipment should be enclosed for a couple of reasons. The first issue is, of course, the presence of dangerous voltage at the fuse protecting the primary of the transformer. In commercial sound systems, it is not unusual to find exposed voltage-carrying components (fuses, 70 and 140 volt speaker output terminal points, filter capacitor cans where the outside of the can itself is intentionally isolated from ground, plate caps on some types of output tubes in older systems which conduct as much as 1000 volts or more). All the more reason why this should be housed in a completely enclosed rack. Simply brushing against some of this stuff can really ruin a person's day... [Linked Image]
The second issue concerns protection from fire. Some components, such as the SS rectifier to the left of the transformer (in the second picture)and some larger resistors in power supplies, can spark upon failure, hence the need for some type of containment. In some sound systems I have installed, I have recommended having a smoke detector attached to the inside of the equipment rack.

It is quite common to find microphone and line-level input cables in the same rack with heavy speaker output and power supply cables. Installers will normally go to great effort to route input cables well away from output and power cables by "dressing" them on opposite sides of the rack as much as possible.

Mike (mamills)


Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *
2023 National Electrical Code (NEC)
2023 NEC Now Available!
 
* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Theelectrikid
Theelectrikid
Levittown, PA
Posts: 812
Joined: April 2004
Top Posters(30 Days)
BigB 4
triple 3
Popular Topics(Views)
302,866 Are you busy
232,026 Re: Forum
216,767 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5