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Home > Archive > Electrical Engineering > March 2006 > Church Lighting 250 watt bulb question
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Church Lighting 250 watt bulb question
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| Larryboy 2006-03-13, 11:21 pm |
| Help! I replaced 12 light bulbs in our church with the highest rated
bulb (250 watt) as printed on the label inside the recessed cans. This
was recommended by a lighting consultant to get the most out of the
lighting equipment we currently have available. This caused the 20 amp
breaker on this circuit to trip the next Sunday. We replaced the 20
amp breaker with a new 20 amp breaker and now all seems to be fine - no
tripping, not overheating, the breaker is cool to the touch, etc. One
of our concerned members decided to have a retired electrician come
out to inspect the circuit and be sure we were OK. The electrician said
that we're most likely overloading this 20 amp circuit, and that we
should only have about 80% of 20 amps X 120 volts = 1920 watts, when
we're actually putting 3000 watts on the 20 amp circuit. Also, the
wire guage is 12 according to the retired electrician. I think I'm
safe if I cut back to six 250 watt bulbs and six 70 watt bulbs.
Now for the questions:
1) Why would this circuit be so under designed for the rated size of
the 12 recessed light cans?
Did the original contractors put in the wrong size circuit and wiring?
2) Would most folks be as dumb as I and think that if the can is rated
for 250 watts, then the circuit should be designed to handle it?
3) The #12 wire size seems small for the distance from the breaker - at
least 75 ft. Is this a concern?
3) These are 40 year old recessed cans, that most likely don't have
thermal switches - should I worry about putting in 250 watt bulbs?
5) We're looking for a commercial lighting consultant to redesign the
whole lighting systems in the main sanctuary, but we haven't had much
luck locating one yet. Anyone know of a good lighting consultant in
South Carolina?
Thank you!
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| Larryboy wrote:
> Help! I replaced 12 light bulbs in our church with the highest rated
> bulb (250 watt) as printed on the label inside the recessed cans. This
> was recommended by a lighting consultant to get the most out of the
> lighting equipment we currently have available. This caused the 20 amp
> breaker on this circuit to trip the next Sunday. We replaced the 20
> amp breaker with a new 20 amp breaker and now all seems to be fine - no
> tripping, not overheating, the breaker is cool to the touch, etc. One
> of our concerned members decided to have a retired electrician come
> out to inspect the circuit and be sure we were OK. The electrician said
> that we're most likely overloading this 20 amp circuit, and that we
> should only have about 80% of 20 amps X 120 volts = 1920 watts, when
> we're actually putting 3000 watts on the 20 amp circuit. Also, the
> wire guage is 12 according to the retired electrician. I think I'm
> safe if I cut back to six 250 watt bulbs and six 70 watt bulbs.
>
> Now for the questions:
> 1) Why would this circuit be so under designed for the rated size of
> the 12 recessed light cans?
> Did the original contractors put in the wrong size circuit and wiring?
We don't know the history, so it's impossible to say.
Might have been properly designed originally, then
added to later on. But it sounds like the lighting
consultant might be remiss...
>
> 2) Would most folks be as dumb as I and think that if the can is rated
> for 250 watts, then the circuit should be designed to handle it?
Most folks don't know even that. They just put a bulb in, often
paying no attention to the ratings. The circuit is *easily* capable
of handling *a* 250 watt can - but not 12 of them. Sounds like
whomever installed them might be remiss...
> 3) The #12 wire size seems small for the distance from the breaker - at
> least 75 ft. Is this a concern?
Technicaly it could be - but you have a larger issue: 3000 watts
on a 20 amp breaker. Bulb "management" is just a bandaid, not a
fix.
> 3) These are 40 year old recessed cans, that most likely don't have
> thermal switches - should I worry about putting in 250 watt bulbs?
Yes. The branch circuit itself is mis-designed. One has to
wonder about the workmanship of the installation, the choice
of the fixtures - everything when there's 3000 watts worth of
fixtures installed on a 20 amp branch. *AND* 40 years of
use may have caused deterioration of the wire's insulation
directly above the cans.
> 5) We're looking for a commercial lighting consultant to redesign the
> whole lighting systems in the main sanctuary, but we haven't had much
> luck locating one yet. Anyone know of a good lighting consultant in
> South Carolina?
>
> Thank you!
>
I don't know about the lighting consultant. But you need to
re-wire, if you want 12 fixtures. Run 2 new 20 amp branches
with 6 lights on each. That makes the wire size vs length
issue disappear; gets rid of old, possibly deteriorated
60 degree C rated wiring; eliminates the excessive current
through the switch (which now belongs in the garbage can) and
the wire and gives you thermally protected cans. It will
dent the church's wallet - so what. As a "place of assembly"
the church, as well as other similar places, has to follow
more stringent rules. See NEC article 518. There may be a
bunch of local fire codes that must be followed - I don't
know. But don't screw around with this. It's a place that
serves the public, and the wiring and construction has to be
right.
Ed
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| TimPerry 2006-03-14, 2:21 am |
|
"Larryboy" <larryboypickle@yahoo.com> wrote in message
news:1142305280.775990.22620@e56g2000cwe.googlegroups.com...
> Help! I replaced 12 light bulbs in our church with the highest rated
> bulb (250 watt) as printed on the label inside the recessed cans. This
> was recommended by a lighting consultant to get the most out of the
> lighting equipment we currently have available. This caused the 20 amp
> breaker on this circuit to trip the next Sunday. We replaced the 20
> amp breaker with a new 20 amp breaker and now all seems to be fine - no
> tripping, not overheating, the breaker is cool to the touch, etc. One
> of our concerned members decided to have a retired electrician come
> out to inspect the circuit and be sure we were OK. The electrician said
> that we're most likely overloading this 20 amp circuit, and that we
> should only have about 80% of 20 amps X 120 volts = 1920 watts, when
> we're actually putting 3000 watts on the 20 amp circuit. Also, the
> wire guage is 12 according to the retired electrician. I think I'm
> safe if I cut back to six 250 watt bulbs and six 70 watt bulbs.
>
> Now for the questions:
> 1) Why would this circuit be so under designed for the rated size of
> the 12 recessed light cans?
its likely that the fixtures met the price, availability, function, and
aesthetic needs of the original designers who expected that 100W lamps would
be used.
> Did the original contractors put in the wrong size circuit and wiring?
>
> 2) Would most folks be as dumb as I and think that if the can is rated
> for 250 watts, then the circuit should be designed to handle it?
it hard to say what most folks would think and be accurate, however you seem
to have encountered a problem and have developed a plan to deal with it.
> 3) The #12 wire size seems small for the distance from the breaker - at
> least 75 ft. Is this a concern?
> 3) These are 40 year old recessed cans, that most likely don't have
> thermal switches - should I worry about putting in 250 watt bulbs?
you should worry about deterioration of the lamp sockets. insulaters that
are falling apart, loose electrical connections, oxidization, pitting on
contacts are signs of aging.
you might consider switching to quartz lamps... more light for the same
power although higher cost per bulb. also harsher white light. this could be
filtered with theater "gels" for effect.
i have seen ceiling cans ("high hats") that are burnt, scorched, and half
melted because the users put standard light bulbs in then instead of
reflector types.
> 5) We're looking for a commercial lighting consultant to redesign the
> whole lighting systems in the main sanctuary, but we haven't had much
> luck locating one yet. Anyone know of a good lighting consultant in
> South Carolina?
>
> Thank you!
>
any architectural company should have one on call.
| |
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| Consider different kinds of bulbs: check out what Home Depot is
offering. You can get a lot of light with a florescence style screw in
bulb.
| |
| Terry 2006-03-14, 11:21 am |
|
Larryboy wrote:
> Help! I replaced 12 light bulbs in our church with the highest rated
> bulb (250 watt) as printed on the label inside the recessed cans. This
> was recommended by a lighting consultant to get the most out of the
> lighting equipment we currently have available. This caused the 20 amp
> breaker on this circuit to trip the next Sunday. We replaced the 20
> amp breaker with a new 20 amp breaker and now all seems to be fine - no
> tripping, not overheating, the breaker is cool to the touch, etc. One
> of our concerned members decided to have a retired electrician come
> out to inspect the circuit and be sure we were OK. The electrician said
> that we're most likely overloading this 20 amp circuit, and that we
> should only have about 80% of 20 amps X 120 volts = 1920 watts, when
> we're actually putting 3000 watts on the 20 amp circuit. Also, the
> wire guage is 12 according to the retired electrician. I think I'm
> safe if I cut back to six 250 watt bulbs and six 70 watt bulbs.
>
> Now for the questions:
> 1) Why would this circuit be so under designed for the rated size of
> the 12 recessed light cans?
> Did the original contractors put in the wrong size circuit and wiring?
>
> 2) Would most folks be as dumb as I and think that if the can is rated
> for 250 watts, then the circuit should be designed to handle it?
> 3) The #12 wire size seems small for the distance from the breaker - at
> least 75 ft. Is this a concern?
> 3) These are 40 year old recessed cans, that most likely don't have
> thermal switches - should I worry about putting in 250 watt bulbs?
> 5) We're looking for a commercial lighting consultant to redesign the
> whole lighting systems in the main sanctuary, but we haven't had much
> luck locating one yet. Anyone know of a good lighting consultant in
> South Carolina?
>
> Thank you!
If 100w bulbs give enough light then that is the way to go.
If you want to use 250w lamps then you could split the fixtures up and
leave 6 on one switch/breaker and add another 20A circuit and put a
switch for the other 6 fixtures.
If your church has deep pockets then go for new stuff. I think the old
stuff is safe. The breaker is doing it's job.
100 ft is the "rule" for voltage drop. You could use a #10 to supply
the new lights.
| |
| Terry 2006-03-14, 11:21 am |
| On 14 Mar 2006 03:23:15 -0800, "Tony" <ajw27703@yahoo.com> wrote:
>Consider different kinds of bulbs: check out what Home Depot is
>offering. You can get a lot of light with a florescence style screw in
>bulb.
These cost much more but last much longer. This is a good way to go
too.
-
--
---
Kilowatt@charter.net When replying by email please leave this signature intact.
| |
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| Beyond the electrical questions, a hint about bulbs in churches and high
ceiling spaces, from a "been there done that in churches"
1) lights are used to put light on a surface -
2) many lights shine the light out from the bulb in a specific direction, in
a shaped beam e.g., narrow spot, spot, flood, narrow flood, wide flood, etc.
The shape can be circular or long.
3) since most lights are used 5-8 feet from the surface, they are rated in
light and diameter at a surface 8 feet from the bulb. And the amount of
light you get in the light circle falls off as the square of the distance
from the bulb.
4) Most church overhead lights are more than 8 feet from the pew.
Thus I had fair success using spots instead of the usual floods to
illuminate the large seating areas, since by the time the beam got to the
pew 12-16 feet down, the circle was a lot larger than it was at its usual 8
feet rating distance. And since I didn't need larger output to get the same
light on the pews, they were lower cost to run, more effective lighting.
I chose bulb types so the light circle (recalculated for the type's
circle size at that distance) to just hit the pew seats, as close as
possible, and we just overlapped the circles to get full church coverage.
In that particular application, outdoor spots (PAR 38?) had a smaller
circle with a better fit at our socket-to-pew distance, and thus a better
beam coverage at the floor, than did indoor (PAR 40) spots.
(If I could have gotten beam-type patterns in the main part of the
church, I would have used them and aligned the beam with the pews, which is
a more efficient lighting scheme. However, we only had the beam-type
sockets up front and were stuck with standard sockets)
As an example of how you can use the bulb's beam shape to get an effect:
We used a fair amount of the lights that look headlights (type escapes me)
to illuminate the huge cross, and those bulbs in the narrow and wide types
give off light in bands rather than circles.
I switched the type from floods to a combination of narrow spots, narrow
floods, and wide floods, and the bulbs were turned and centered so that
their light band long axis matched the axes of the cross and on the altar.
That light made the cross almost glow on the cloth background.
fwiw
"Larryboy" <larryboypickle@yahoo.com> wrote in message
news:1142305280.775990.22620@e56g2000cwe.googlegroups.com...
> Help! I replaced 12 light bulbs in our church with the highest rated
> bulb (250 watt) as printed on the label inside the recessed cans. This
> was recommended by a lighting consultant to get the most out of the
> lighting equipment we currently have available. This caused the 20 amp
> breaker on this circuit to trip the next Sunday. We replaced the 20
> amp breaker with a new 20 amp breaker and now all seems to be fine - no
> tripping, not overheating, the breaker is cool to the touch, etc. One
> of our concerned members decided to have a retired electrician come
> out to inspect the circuit and be sure we were OK. The electrician said
> that we're most likely overloading this 20 amp circuit, and that we
> should only have about 80% of 20 amps X 120 volts = 1920 watts, when
> we're actually putting 3000 watts on the 20 amp circuit. Also, the
> wire guage is 12 according to the retired electrician. I think I'm
> safe if I cut back to six 250 watt bulbs and six 70 watt bulbs.
>
> Now for the questions:
> 1) Why would this circuit be so under designed for the rated size of
> the 12 recessed light cans?
> Did the original contractors put in the wrong size circuit and wiring?
>
> 2) Would most folks be as dumb as I and think that if the can is rated
> for 250 watts, then the circuit should be designed to handle it?
> 3) The #12 wire size seems small for the distance from the breaker - at
> least 75 ft. Is this a concern?
> 3) These are 40 year old recessed cans, that most likely don't have
> thermal switches - should I worry about putting in 250 watt bulbs?
> 5) We're looking for a commercial lighting consultant to redesign the
> whole lighting systems in the main sanctuary, but we haven't had much
> luck locating one yet. Anyone know of a good lighting consultant in
> South Carolina?
>
> Thank you!
>
| |
| repatch 2006-03-14, 2:21 pm |
| On Mon, 13 Mar 2006 19:01:20 -0800, Larryboy wrote:
> 2) Would most folks be as dumb as I and think that if the can is rated for
> 250 watts, then the circuit should be designed to handle it? 3) The #12
> wire size seems small for the distance from the breaker - at least 75 ft.
> Is this a concern?
I can't answer to much about the code issues, but have you considered
going compact flourescent? Large power savings, same amount of light, last
much longer. I haven't personally seen a CF bulb that gives the equivalent
light as a 250W bulb, but I'm sure they're out there.
TTYL
| |
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| Larryboy wrote:
> 5) We're looking for a commercial lighting consultant to redesign the
> whole lighting systems in the main sanctuary, but we haven't had much
> luck locating one yet. Anyone know of a good lighting consultant in
> South Carolina?
>
I won't duplicate the electrical answers, just agree. But I can help on
the lighting consultants.
I am one myself and recommend that you check
http://ncqlp.org/registry/
(National Council on Qualifications for the Lighting Professions)
There you can search for qualified people. Not all of the listed folks
will be able to help you, as they may not be independant consultants.
They surely will know who can.
Many folks are involved in lighting and many of them are excelent but,
"LC" is the only professional lighting certification.
RickR
| |
| Phil Munro 2006-03-16, 10:21 am |
| repatch wrote:
> On Mon, 13 Mar 2006 19:01:20 -0800, Larryboy wrote:
>
>
> I can't answer to much about the code issues, but have you considered
> going compact flourescent? Large power savings, same amount of light, last
> much longer. I haven't personally seen a CF bulb that gives the equivalent
> light as a 250W bulb, but I'm sure they're out there.
>
> TTYL
Take a look here for CFL info: http://www.tcpi.com/index.php
--
Phil Munro Dept of Electrical & Computer Engin
mailto:PcMunro@cc.ysu.edu Youngstown State University
Youngstown, Ohio 44555
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