100 ft, 12 Gauge Heavy Duty Outdoor Extension Cord for $7.97

[JR]

Or somebody needs to move the inventory and is pricing it accordingly.

[LCHIEN]

A couple of points that may result in their cost being lower than current spot market pricing:

1. They buy in large quantities, so the price is usually lower that spot.

2. They have contracts in place to buy materials for years at a specified price. If their contract says $1/lb for the next 3 years, that's what they pay, regardless of market price.

3. Some governments effectively subsidize materials cost - so the company may only pay $1/lb when market is $2.90/lb as a result of government subsidies, tax credits, etc. (our government does the same thing for some materials)

4. Until recently, copper prices were substantially lower. Given typical production cycles, these cords were likely manufactured 4 to 6 months ago - when copper prices were lower.

If the product is advertised as a 12 guage cord, however, the wire must be 12 guage by law or it's fraudulent advertising and a host of other infractions. I haven't encountered any such deception on the part of Harbor Freight, ever.

Now I'm curious, though - might just get one and check it out.

The price I saw was per pound in lots of 25 tons - so there won't be much lower prices than that.
Yes, historically the low in the last 12 months was 1.27 per pound, so the copper content of a 100 ft 12 gauge cord would be around $7.62 if they bought 25 tons at the low point in the last year.
Yes, the Chinese government subsidizes business by pegging the chinese currency low to keep their products very competitive.
Still, assuming they bought 25 tons last year at the very bottom prices, $7.62 would only buy you a large ingot of copper which is a long way from a usable extension cord. And 37 cents left from $7.97 to make it more useful.
First you have to draw the fine wires, probably 19 strands per 12 gauge wire for not too flexible cord. Then you have to use a large winding machine to spin the 19 strands together to make a 12 gauge wire and spool it.
Then you have to shoot a jacket over each 12 ga wire in three colors. and respool it.
Then you have to take three spools and assorted spools of filler material (to make the final cord roundish instead of a triangle) and spin them into a 12/3 and then overshoot a PVC jacket over that with printing.
THen you have to cut to 100' lengths and terminate into plug contacts and then use a molding machine to overmold a plug body over that. testing, Packaging, shipping and markups somewhere along the line...
So you can see there's still a lot to be done for 37 cents after you buy the copper.

[woodturner]

Incidentally Kaydee is right about pricing. Market prices for raw copper are about $2.90+ per pound (todays market price), 3 x 100 feet of 12 gauge copper wire would weigh just shy of 6 pounds, so raw copper for 12/3 would cost nearly $18. - not counting stranding, drawing and spooling the bare wire, insulating and spooling the inividual wires, then jacketing an filling the whole cable then attaching and molding the connectors, labor and materials, packaging and shipping. Even with free labor the Chinese can't do that.

A couple of points that may result in their cost being lower than current spot market pricing:

1. They buy in large quantities, so the price is usually lower that spot.

2. They have contracts in place to buy materials for years at a specified price. If their contract says $1/lb for the next 3 years, that's what they pay, regardless of market price.

3. Some governments effectively subsidize materials cost - so the company may only pay $1/lb when market is $2.90/lb as a result of government subsidies, tax credits, etc. (our government does the same thing for some materials)

4. Until recently, copper prices were substantially lower. Given typical production cycles, these cords were likely manufactured 4 to 6 months ago - when copper prices were lower.

If the product is advertised as a 12 guage cord, however, the wire must be 12 guage by law or it's fraudulent advertising and a host of other infractions. I haven't encountered any such deception on the part of Harbor Freight, ever.

Now I'm curious, though - might just get one and check it out.

[LCHIEN]

Wouldn't another way to tell if it's really 12ga be to weigh the cord? 300' of 12ga copper weighs about 6lb, but 300' of 16ga copper weighs a bit over 2lb. Of course there's a lot more weight in the insulation, jacket, and connectors. Still, comparing with a known good cord of same length, there should be a noticeable difference.

Or another thought: How about using a load that won't blow out from undervoltage, like a 1750 watt electric frying pan or something, and then measuring voltage drop at the end of the cord compared to a known good cord? That Kill-a-watt could be handy for such a test.

May be a moot point as my order is backordered and the cords themselves are NLA.

Using a mostly resistive load of known or measured amperage (heater, Hair dryer, electric skillet, toaster, etc drawing 1200-1800W) and using the Kill-a-watt to measure the voltage first at the head and then moving to the tail end would be a pretty good way. The K-W could be used to measure the amperage, too. With .32 total ohms (12 ga) and a 15A load, there should be nearly 5V drop ( and the K-a-W has a .1 V resolution). Should be easily distinguishable from .5 ohms (14 ga, 7.5V drop) and .8 ohms (16 ga., 12V drop).

Weighing it would be another way, but its a bit clouded because they will be making up wire gauge drop by increasing insulation, which while less dense, will not be so obvious because as a percentage change from the whole weight of the cable, will be much less change than the change in resistance. Without looking up the density pf PVC and calculating the volumes and weight, lets guess in a good 12 gauge cord, there's 6 lbs of copper and 12 lbs of PVC (because of inner and outer jackets, and increasing volumes to the outside radius etc, even tho the density be maybe 1/3, the volume may be 12x as much as the copper volume). So take away 1.5 lbs of copper and replace it with 0.5 lbs of PVC, you've chnaged the weight from 18 lbs to 17 lbs. It'd be much less obvious. A 5% change in total weight is less obvious or conclusive than a 50% change in resistance or voltage drop.

[tjr]

Wouldn't another way to tell if it's really 12ga be to weigh the cord? 300' of 12ga copper weighs about 6lb, but 300' of 16ga copper weighs a bit over 2lb. Of course there's a lot more weight in the insulation, jacket, and connectors. Still, comparing with a known good cord of same length, there should be a noticeable difference.

Or another thought: How about using a load that won't blow out from undervoltage, like a 1750 watt electric frying pan or something, and then measuring voltage drop at the end of the cord compared to a known good cord? That Kill-a-watt could be handy for such a test.

May be a moot point as my order is backordered and the cords themselves are NLA.

[Uncle Cracker]

They have an analog bar graph at the bottom to resolve that flickering needle hangup you have.

I wouldn't call it a hangup, Loring... I've just spent a lot of time looking at oscillating circuits in a ditch someplace when I didn't have my scope with me...

[LCHIEN]

Simpson 260's were old but standard technology when I was a wee engineer.

Even Fluke 87s are now old - I think the first generation came out in around 1984?
They have an analog bar graph at the bottom to resolve that flickering needle hangup you have.

[Mr__Bill]

So do I. It's an older Simpson 260 series, and it will be alive long after I'm dead... It's useful to me often, as the digitals often do not load a circuit enough to get an accurate reading. They will sometimes see voltage potential that is not really there in the real sense of doing work. IMHO a needle meter will also give a better sense of an oscillating voltage than a DMM, because you're watching a needle wagging, as opposed to a momentary reading from a DMM determined by its sampling rate. The trick is just to know when to use one and when to use the other.

This is very true, just try and get a power output from an amplifier with a digital, but with an analog you're almost able to hear it and name that song too!


Bill.

[cgallery]

Thanks for the explanation Loring!

[Uncle Cracker]

I still have one that is analog too

So do I. It's an older Simpson 260 series, and it will be alive long after I'm dead... It's useful to me often, as the digitals often do not load a circuit enough to get an accurate reading. They will sometimes see voltage potential that is not really there in the real sense of doing work. IMHO a needle meter will also give a better sense of an oscillating voltage than a DMM, because you're watching a needle wagging, as opposed to a momentary reading from a DMM determined by its sampling rate. The trick is just to know when to use one and when to use the other.

[LCHIEN]

Loring, are modern (high-end) DMM's precise enough for this? At what point do you need a bridge? Or do higher-end DMM's implement some sort of bridge?

Bill, a DMM (Digital Multi-meter)is a special case of a VOM (Volt-ohm multimeter) - in that it has a digital readout, whereas a VOM can be digital or analog. Also a DMM may be more than just ohms and volts, it may do frequency, capacitance, amps, etc.


Phil, a modern DMM has the accuracy and resolution. The resolution is 0.1 ohms on the lowest ohm scale of my meter which is enough. But, you have to be careful.
If you take a decent DMM like this Fluke 87 i have in my hands now, and casually touch the probes to each other i get numbers bouncing from .3 to 1.6 ohms. Once I bear down hard and rub them to get oxides, dirt and crud and stuff off i get a steady 0.2 ohms. If I can do this then that's OK, I know now that teh meter resistance indicated .2 ohms and can subtract this from any further readings. You have to do the same with the prongs an sockets on the ext cord being measured... clear off the crud on the prongs, use the points on the probes to scratch down to the bare metal. If I read 0.5 then I know its 0.3 in the cord now takin off the meter/probe reisstance i measured earlier. Not a 1% measuremnt anymore but good enough to tell if its 12 gauge or 14 or 16 gauge. That's why i recommended measureing round trip, to double the detectable resistance. Nice meters like the Fluke have a REL button which allows taking off the probe&meter resistance and setting the readout to zero, so the meter only reads the load resistance.


More expensive bench meters will use four-wire ohms measurement where a meaureing current is sent down a pair of probe wires connected to the load being measured. Then a separate pair of voltage lines is used to measure but not carry current to the end points (e.g. the load terminals, not the instrument ends of the test probes which carry the measurement current) to sense the voltage induced at the end of the load resistance. that eliminates the probe effects.

bridges are usually used to measure complex resistances under various DC bias and AC frequency and amplitude conditions which you encounter in non-linear loads.

[RAV2]

Cool thread and a lot of good info.

Ad has been taken down.

Must have been a pricing error.

[Mr__Bill]

Oh ****, is my generation showing calling it a VOM instead of a DMM? I still have one that is analog too


Bill, with way too much time on his hands today...

[cgallery]

Loring, are modern (high-end) DMM's precise enough for this? At what point do you need a bridge? Or do higher-end DMM's implement some sort of bridge?

[Mr__Bill]

There is an easy, non destructive way to tell, you can just measure the resistance. 12 gauge should have abour 1.6ohms/1000 feet, or .32 ohms if you tie both prongs together at the male end and measure the resistance between slots at the female end of a 100 feet cable. A 16 ga. would have 0.8 ohms resistance measured the same way. 14 ga, 0.5 ohms.

Thanks, that's good to know, or in my case to print out and put with the VOM.

As an aside, first check at the male connector's prongs to make sure that the shunt is at 0 ohms.

Bill,