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Joined: Aug 2002
Posts: 1,691
SvenNYC Offline OP
Has anyone ever stopped to notice that General Electric's 75 watt lightbulbs and (I think also) 100 watt bulbs are only rated for 750 hours of use?

These are the kinds normally sold in the big-name supermarkets and in corner groceries at pretty outrageous prices for a 4-pack.

Meanwhile, the off-brand Chinese bulbs (4 bulbs for a dollar) available from the dollar stores are usually claiming 2,000 to 5,000 hours of use.

I've noticed the off-brand bulbs are usually rated for 130 volts, while GE's are rated for 120. And I've also noticed that the Chinese bulbs do last significantly longer (filaments are also better supported)

What I'm wondering is if GE actually designs its 75watt+ bulbs around a rating of 110 and then marks them up with a 120 volt rating in order to:

1) make the bulb burn brighter

2) make them burn out faster so you have to buy more bulbs.

It's a CONSPIRACY, I tell ya! [Linked Image]

Any thoughts?

Joined: Jul 2004
Posts: 625
That's a general problems with Type-A's--they just burn themselves out faster. They often succumb to heart attacks, but there are a host of other problems that Type-A's tend to be affected by, too. [Linked Image]

Joined: Jan 2002
Posts: 1,457
The 130 volt "Chinese" bulbs are not going to give you 75 watt light output. Never ever buy lightbulbs in a supermarket, the markup on those things is huge. Get them from the grassy knoll. [Linked Image]

Joined: Aug 2002
Posts: 1,691
SvenNYC Offline OP

This is true. I buy 130-volt 60 watt bulbs and they're probably using maybe 50-something watts and putting out a tad less light than a "normal" 60 watt bulb would.

I've gotten used to the slightly reduced light output though. It's barely noticeable.

No, I don't buy bulbs at supermarkets or grocery stores. I get the 4 packs from dollar stores or job-lot stores. [Linked Image]

Joined: Nov 2003
Posts: 127
The vast majority of bulbs in my house are CFL's; I only use incandescent bulbs where short "ON" cycles are typical.

FWIW, I just ordered two cases of 67-watt traffic signal bulbs that should be on my doorstep any day now. I ordered them solely for their long life (8000 hours rated), certainly not for their lumens per watt. My brother had one in his outdoor post lamp which lasted, according to him, fourteen years(!).

True, they don't make bulbs any more like that one in a California fire station (100 years?!!!)- planned obsolescence...

No wire bias here- I'm standing on neutral ground.
Joined: Sep 2002
Posts: 931
Likes: 1
The state of California was selling cases and cases of traffic signal lamp at their surplus outlet a while back I think they wanted $10.00 a case. (new)

Joined: Sep 2003
Posts: 119
Does any one know a websites that explains bulb codes? and shapes A B Par BT G etc? Thanks I alswonder what those mean

Theres always enough room in the junction box.You just need a bigger hammer
Joined: Jan 2003
Posts: 4,391
Something that is good to know is that lamp numbers mean the size.

A "T-8" fluorescent lamp is a Tubular lamp 1" in diameter.

T-5 is 5/8" in diameter.

The numbers represent 1/8s of an 1".

Why 1/8s of an 1"?

I do not know. [Linked Image]

An R-40 is an Reflector lamp 5" in diameter. 40 / 8 = 5

An S-11 is a Sign lamp 1 3/8" in diameter.

The lamps we are most familiar with are Type A lamps

A-19, A-21, A-23 are common sizes

An A-21 would be 2 5/8" in diameter

Some more info can be found on these links

Incandescent Lamps

Fluorescent Lamps

HID Lamps

Oh yeah you asked about a PAR lamp

PAR = Parabolic Reflector lamp

PAR 38 is a typical outside flood light used for years and it is 4 6/8" or 4 3/4" if you reduce the fraction, in diameter.


[This message has been edited by iwire (edited 12-04-2004).]

Bob Badger
Construction & Maintenance Electrician
Joined: Nov 2002
Posts: 267
Lamps that confuses me is the fluorescent designators for example:
F= fluorescent
96= 96" or 8' long
T= tubular
12= 12/8ths
CW= cool white

But the 4' lamps run differently such as
40 = 40 watts instead of inches
32= 32 Watts
Also what is the real meaning behind a 741, I know it's closer to a cool white and it has something to do with K factor but, why is there a 3500k or some say 735 as high as 850, how do these associate with each other K and the three digit number??

Joined: Mar 2004
Posts: 804
Ever notice at the supermarket they have 150 and 200 watt incandescents on the shelf? Guess where they end up? In the 100 watt rated vapor proof fixtures in the walk in coolers. I have several boxes of these fixtures I kept after we swapped the fixtures out for energy saving flourescents. The only thing wrong with them is all the sockets and wires are fried. Oh and I got a good supply of 150 and 200 watt lamps!

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