CFL ballast polarity?

Jim, A CFL is a two-terminal device. It doesn't know, nor does it care which color wire is connected to its center pin or threaded base. It will even work if the ground and neutral are reversed (assuming that ground and neutral are solidly connected in the breaker panel or fusebox). So long as there is a complete circuit for the current to flow, and sufficient voltage is present, it will work. However, electronic devices are subject to failure at any time, especially CFLs, which haven't shown a high reliability track record as yet. Other factors to be considered in determining reliability and causes of failure of CFLs include mounting position, ventilation, AC supply cleanliness (lack or presence of damaging surges, spikes, sags, etc.) and operating temperature, to name a few.

Cheers

Any 120 VAC-rated CF lamp should work properly in a socket wired for 120VAC.

Reading about the differences between AC and DC should clear up the polarity question for you.

As far as conventional wiring in the USA..

All or most presently made lighting fixtures/lamps are wired with the center contact going to the switch, then to line/hot. All newer fixtures/lamps have polarized plugs on the cords (one plug blade wider than the other, with the wider one being neutral). The outer/threaded portion of the socket is neutral (not hot/line) so that if a persons' fingers were to contact the threaded base of the bulb/lamp, they would not receive a shock, eliminating the likelyhood of accidental electrocution.

Antique lighting fixtures/lamps didn't have polarized plugs on the power cords, so the contacts in the sockets may have been either hot or neutral. Unless an old lighting fixture is being wired for historical accuracy (museum, historical film or toured historical building), the old non-polarized power cord should be replaced with a polarized power cord, and wired properly with the hot lead connected to the switch, and the lead from the switch connected to the center contact of the socket(s) and the neutral lead properly connected to the threaded portion.

If any of this is even slightly unclear to you, you need to get the help of a qualified and experienced person with an electrical background, to eliminate any possibility of creating a potential shock hazard. A qualified person will be familiar with the proper types of wiring and connections required for a safe repair.

-- Cheers, WB .............

"Wild_Bill" wrote in news:F1w_l.221806$ snipped-for-privacy@en-nntp-01.dc.easynews.com:

"Polarity" is just a loose term, if not technically precise for AC.

This is an old lamp to be installed in a ceiling fixture. It has two black wires with no obvious hot vs. neutral. I'll just do a continuity check for the center post and make that wire hot.

Jim

Any old wiring should be/needs to be replaced, especially any that has any brittle insulation.

Old rubber insulated and/or fabric covered wire should not be in use today. A few feet of proper temperature rated, new appliance wire probably won't even cost $5, and allows the old lighting fixtures to be brought up to today's standards.

Any time vintage or antique equipment is reused, it should be fully inspected for secure contacts/connections. Any corroded or pitted electrical connectors should be discarded and replaced with updated parts. Ordinary oxidation can be cleaned off of the electrical connectors to insure clean, low resistance connections that won't overheat and fail.

-- Cheers, WB .............

y.

I hate to get too far off topic, but I have a comment on this.

I replaced plugs on several multivoltage appliances this year because I couldn't find adaptors locally.

Buying new wire is easy. Buying a quality plug for the end of it, on the other hand, is difficult to impossible. I tried all the local big box stores, plus the specialty hardware stores, all anybody had was cheap offshore junk. Maybe the electrical contractor dealers have better stuff, but they don't sell to everybody.

"Polarity"?

It should work fine either way.

Finding high quality plugs and receptacles isn't difficult here, there are still other real distributors here that primarily sell to contractors or maintenance organizations, but also welcome consumers that know and appreciate high grade components.

I can get Hubbell and other better grade parts, and even medical grade power cord parts, by walking in and asking for them, without having to place special orders or ordering online/phone orders and waiting.

The big box/borg stores carry replacement power cords suitable for power tools and many appliances. Some of them are low quality, although some have solid brass plug blades (not folded over thin brass sheetmetal) and SJ jackets with heavier gauge wire. If I see some 8-10 ft extension cords that appear to be durable (even though you never really know about molded cord ends), I sometimes buy them and end up cutting off the receptacle end to use the cord as a replaement power cord.

The key to most of this stuff related to simple repairs, is to buy these components any time you see them, so you don't have to try to find them when they're needed. I've bought new in-package stuff from flea markets, garage sales and on eBay at drastically reduced prices. Some materials can be trusted if they are new, but other components like circuit breakers, GFCI receptacles, I'll only buy from established loal retailers.

-- Cheers, WB .............

I hate to get too far off topic, but I have a comment on this.

I replaced plugs on several multivoltage appliances this year because I couldn't find adaptors locally.

Buying new wire is easy. Buying a quality plug for the end of it, on the other hand, is difficult to impossible. I tried all the local big box stores, plus the specialty hardware stores, all anybody had was cheap offshore junk. Maybe the electrical contractor dealers have better stuff, but they don't sell to everybody.

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rubber insulated and/or fabric covered wire should not be in use

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Buy a cheap extension cord and cut off the female end.

Cheaper is to always carry a wire cutter and stop at every curbside junk pile. Throw away nothing electrical without first taking the cord.

On 6/20/2009 7:17 PM Frank spake thus:

I do that all the time. I never have to buy power cords.

No. the lamp does not care which AC line goes to which pin.

AMEN! We're starting to sound like Algernon (the mad scientist from the Beatles' movie "HELP") It's the plugs, you know . . . must use good British plugs . . .

I have a box of huge machine/industrial 3-prong plugs with strain relief for huge wires but they're overkill for most things. And the hang-tab Eagle Electric household ones with NO strain relief. Nothing in between.

I was mildly shocked by an old ceiling lamp (fixture?) by the turn-switch built into an Edison socket's base. The knob was originally plastic coated with a metal rod inside, but enough of the plastic wore off for the metal to make contact with something "hot" and to me. I'm unsure if it was somehow touching the side, or directly conducting from the center-pin-switch. but it was not something obvious from inspection!

A neighbor did that, discarding 26 feet of the outlet end, so I attached a plug and I've got a nice extension cord.

That's why I have a box of new high quality plugs waiting for uses: cheap at a garage sale.