Re: Circuit tester question
Hello-
What you are reading is two hots in the outlet, and should be confirmed ASAP.
In most cases, this is of course incorrect wiring. However, Article 647 of the 2002 NEC allows what is called technical power for sensitive electronic equipment, which consist of two, 60 volt hot conductors in a receptacle. The receptacle is required to be clearly labeled "Warning- Technical Power. Do not connect to lighting equipment. For electronic equipment use only. 60/120 v 1 phaseAC. GFCI protected." (2002 NEC 647.7(A)(2))
One comment about those three-lamp circuit testers, taken from NFPA standard 70B "Recommended Practice for Electrical Equipment Maintenance":
"Although these test devices can provide some useful and easily acquired information, some have limitations, and the test results should be used with caution. An incorrect display can be considered a valid indication that there is an incorrect situation, but a correct wiring display should not be accepted without further investigation."
You may also want to check out an article I wrote for Occupational Health and Safety magazine in June of 2000 titled "Using Circuit Analyzers". I believe that the article can be found online, and covers different problems with these three-lamp testers.
Hope that Hurricane Francis passed you by safely- my folks are down in Port St. Lucie, about 2.5 miles from original landfall. Who knows how these things work- no damage to their home, but neighbors on either side weren't so lucky.
Best wishes,
Mark