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Q: T4 lamps ( Answered,   1 Comment )
Subject: T4 lamps
Category: Science > Technology
Asked by: besparkle-ga
List Price: $2.00
Posted: 07 Sep 2006 15:55 PDT
Expires: 07 Oct 2006 15:55 PDT
Question ID: 763180
I know that the T in T4 stands for Tubular.  What does the 4 stand
for? (in the case of a T4 lamp) or the 5 in the case of a T5 lamp?

Thank you
Subject: Re: T4 lamps
Answered By: denco-ga on 07 Sep 2006 22:05 PDT
Howdy besparkle-ga,

The comment by stanmartin1952-ga is absolutely correct in that a T4 lamp
is 1/2" in diameter.  But, what if it is a T5 or T8?  The website of the
UK based Lamp Company provides the answer for us on one of their Glossary

"T2, T4, T5 , T8, T12"

"Refers to the diameter of a fluorescent tube (in 1/8th of an inch) ..."

So, a T5 lamp should be 5/8" in diameter, and the "Lighting Research Center"
website from Rensselaer Polytechnic Institute's National Lighting Product
Information Program verifies that, and provides illustrations and metric
conversions as well!

"T5 lamps have a diameter equal to 5 times an eighth of an inch, or 5/8"."

If you need any clarification, please feel free to ask.

Search strategy:

Google search on: T4 T5 lamps

Looking Forward, denco-ga - Google Answers Researcher
Subject: Re: T4 lamps
From: stanmartin1952-ga on 07 Sep 2006 18:28 PDT
T4 seems to stand for 1/2" diameter:

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