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 (), 39 guests, and 21 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#127783 12/19/01 10:45 PM
Joined: Dec 2001
Posts: 37
A
aphares Offline OP
Member
I encountered something new today about phototcells, but I'm still unsure of how or why I had the problem.
A 120v photocell was cycling on/off in intervals of about five minutes. Now there was a lighting contactor 120v on the load side that pulled approximately .75amps. Also on the load side was two ice cube relays that were 120v coils, that pulled at best .5amps. they were a (honeywell)"for hvac" style relay. that was used to contact other hps lighting. and one neon light.
My first guese was a bad photocell, but I have never seen one cycle before, so further testing was done. by process of elimination.
When the two "honeywell" relays were unhooked from the load side, and only the lighting contactor was hook-up than the cycling would not happen any longer.
Was it all pulling too many amps ? NO. I determand this early on. Even at that is it not that the photocell is rated for it's draw, 15/20amp depending on the rating.
Both "honeywell" relays worked properly.
Was the resistants to high across the three coils ? causing the photocell to see more of a load than what was real. in this case if it exceeded the breaker rating, than why was it not tripping ? (porperly rated). With a digital amp meter the amperage was never a question.
History: the photocell cycled once before, a electrician replaced it about a month ago. I believe he tested the lights in the day, seen they where on, then left. A month later it was noticible they were cycling again. So a new electrician was called. So the photocell was 1 month old. The other relays got hook-up during a remodel, about a year ago. So it's a good possibility that this worked for up to a year in this manner.
I have only seen a photocell good or bad.
It was all wired to code, the "honeywell relays was removed, and the other lighting was routed to the lighting panel, controlled by the lighting contactor. All works fine now, but I'm still dont know why it was cycling ????????

#127784 12/19/01 11:14 PM
Joined: Dec 2001
Posts: 37
A
aphares Offline OP
Member
P.S. All testing was done with tape over the eye. So false lighting was not the cause.

#127785 12/22/01 10:15 PM
Joined: Jun 2001
Posts: 642
N
Member
Most of the time I have had a service call about this problem, I found the line and load wires on the photocell to be wired up backwards. ALmost all the rest the photocell was replaced to fix the problem.


ed

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
Potseal
Potseal
Saskatchewan
Posts: 264
Joined: February 2013
Top Posters(30 Days)
BigB 9
triple 3
Popular Topics(Views)
302,469 Are you busy
231,870 Re: Forum
216,491 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5