Neutral prong on Christmas light plug

I bought a few sets of Philips mini Christmas lights this morning. As I was putting them on the tree, I noticed something about the plugs and sockets.

1: The plug does not have a wide neutral prong. 2: The socket on the back of the plug will not accept a wide neutral plug because there is no wide neutral slot. 3: The socket at the end of the string *will* accept a wide neutral plug since it has a wide neutral slot.

I wonder why that it is. Yes, it allows me to string together lights from other manufacturers that use a wide neutral plug, but there is no guarantee that the neutral is actually connected to the neutral because the Philips plug doesn't force the user to orientate the plug in any given manner.

Why not build the plug and socket at the start of the string with a wide neutral prong and slot or build the socket at the end without one? Why mix and match?

Reply to
DerbyDad03
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Well, the reason for no wide neutral on the "piggyback" is so you cannot connect a high-power load through the "piggyback" plug. Why they put it on the end IS a good question - it should NOT be polarized if the primary connector is not.

Reply to
clare

Hi, I think newer ones seem to have polarized plug/receptacle. Some of old strings I have are not like that. To mix them, I just snip off wider blade little bit. For last couple years mixing them, nothing bad happened.

Reply to
Tony Hwang

I thought by law that all new electrical stuff, unless double- insulated, had to have polarized plugs. You may have bought some really old lights.

Reply to
hrhofmann

I'd be surprised to find that Target is selling "really old lights", but it's possible. All of their Philips lights (hundred of boxes, all different quantities and colors) had the same box design, which would mean that everything that they had on the shelf would have to be really old to be of the same design vintage.

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mini lights

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Besides, even if they were really old, you wouldn't expect to find a polarized socket on one end would you?

Maybe I'll call Philips tomorrow and inquire.

Reply to
DerbyDad03

It really has nothing to do with double insulated in this case. The 2 pin (2 wire) bulbs are not polarized (no screw shell) so there is no requirement to polarize the string.

Reply to
gfretwell

Or they were made in China, and that stuff dont follow the electrical codes.

One of the old adaptors to convert a 2 prong outlet to 3 prong grounded plugs will often fit into those plugs and then the wide prong might fit. Otherwise, just use a grinder and make the wide prong narrower.

Reply to
homeowner

If the lights are Chinese, there may well be issues with plugs. It runs in my mind that there are places in the world with non polarised sockets similar to yours.

In the UK we have had moulded on plugs that are deadly from China..

Reply to
harry

And pointless anyway as they are wired in series.

Reply to
harry

That doesn't address the question of having a wide slot on the socket at the end of the string but not on the socket at he plug end.

If you have other sets of lights with a polarized plug (I do) you can't plug them into the plug end of the Philips sets, you have to plug them into the socket end, which is not always what I want to do.

Reply to
DerbyDad03

I've read all these replies, but I really think I have an answer. I too have always wondered, but for me I've wondered why are these things polarized. I think I have an answer. On older light strings, with a non polar plug, they usually have 2 fuses in the plug so if the plug it put into the socket in either way, the hot will have a fuse. In essence, because the lights in the strings are wired in series, the 2 fuses are also in series. But the safety aspect is that if something shorts to earth ground in the beginning of the string, it should take out the fuse that's on the hot side, whichever way it is plugged in. BTW, the second reason for the fusing itself is that in each bulb there is a shunt which 'activates' when the bulb's filament burns out (opens), thus keeping the circuit complete and keeping the remaining lamps lit (if the shunt actually works!). If multiple bulbs in the string burn out, you can get to a runaway situation where more and more current flow, burning out more and more lamps until all that is left is shunts. The fuse(s) protect against the large currents causing bad things to happen with the bulbs and/or wiring. But, of course, for this case only one fuse is needed. So, to save on putting in the 2nd very cheap fuse, they only put one fuse on the hot side and use polar plug to guarantee it. BTW, some older strings had 2 special bulbs, which were called 'fuse bulbs' which apparently didn't have shunts and usually had some green paint on the bulb. They usually had a different base, so a regular lamp could not be plugged in these special sockets. But these seem to have disappeared through the years. So now, we seem to be stuck with this polar stuff. A small file or a moto tool works wonders, but I always make sure they are plugged in the 'right' way .... yeah sure :)

Reply to
Art Todesco

Things made in China frequently have "little problems" like this. Either because they can't read U.L electrical standards which are in English, or because they just don't care.

Report the product to the US Consumer Product Safety Commission. They already have tons of recalls on Chinese made electrical products which are counterfeit or unsafe. This will add to the list...

Here is an example of WHY plugs are polarized - makes changing a regular light bulb safer...

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Reply to
Bill
[snip]

BTW, some older strings had 2 special bulbs, which were called

I don't remember any with green paint. I do remember 'flasher' bulbs with red paint. IIRC, those didn't have shunts.

[snip]
Reply to
Mark Lloyd

A string of lights has no "chassis" or anything to reference to neutral, so no polarization is required.

Reply to
clare

Never seen a fuse in the plug of an "american style" plug - ot ANY

115 volt plug, for that matter.
Reply to
clare

Then you haven't purchased cheap Christmas lights recently. They all have them and usually include spares in with the spare bulbs. They are tubes of glass with metal on the ends - just like fuses you may be used to but much smaller. I don't have any here, but from memory, they are about 1/2 inches long. I have never had to use one, though.

Reply to
Pat

Christmas lights strings have had fuses built onto the plug for many years. There is a small slide out panel in the plug that reveals the fuses.

See here...

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Reply to
DerbyDad03

When you say "older light strings", what do you mean?

I bought the lights with the non-polarized plug at Target yesterday. How long would they have to have been in their warehouse to be what yopu consider "older"?

(BTW...I kind of agree with what you are saying, except for the "older" part. I don't really think that I bought "older" light strings, but I could be wrong.)

Of course, none of what you've said seems to answer my original question - if they don't use a polarized plug or socket at the start of the string, why do they use a polarized socket at the end?

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Reply to
DerbyDad03

Actually, I've never seen that and I have lots of light strings of various age and lengths. That's just plain wrong. I don't know how it could have been UL approved.

Reply to
Art Todesco

Where are you buying these - and when you say cheap, how cheap?

Never seen one in Ontario Canada at Canadian Tire or Home Hardware or Walmart (have not looked very hard at Walmart - I try not to patronize them).

Reply to
clare

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