Don't run a heater from a power strip even a appliance cord is a bad idea I see maybe 20 of these a year that burn up the problem is
the wall outlet in most houses are cheap. You then plug a heater in and they heat up making the outlet spring weaker the cord adds more resistance to the heater making it pull even more.

How is it that adding series resistance causes the heater to pull even more current?

 

As a general rule, you can have conductors too big, but you can't have them too small.
You need to consider the complete current carrying path and in my experience, the weak points are not so much cable size but stuff like terminal blocks and plug contacts. Copper/brass oxidises and pushes the resistance up. Screw-down terminals where the screw directly winds down on the conductors are unreliable and prone to loosen up as the copper settles down a bit, especially with multi-strand conductors - 6-months later, they need tightening again. Having made up a lot of industrial panels, screw-down terminals would be a no-no. At the very least they would have a wire protection leaf so the screw doesn't bear directly onto the conductor. Stranded conductors would always have a ferrule (bootlace ferrule) crimped on first, or at a pinch, even soldered, plus you get the additional protection from wayward unsecured strands.
Plenty of devastating fires start in out of the way junction boxes and even in properly installed circuits which are not inspected or tested regularly.
Most of the stuff used in industrial settings were a better quality than domestic, domestic being at the cheap end. There is a rating classification certainly for electronic equipment which in order of ascending cost/quality goes something like Domestic, Commercial (office etc.), Industrial (factories etc.), then Medical, Nuclear, Aerospace and Military.
The Chinese are getting better at production, but as you found out, there is a big difference between mainland China and Taiwan, who I rate as very competent engineers. My heart sinks when I see PRC on the label.

 

Stranded conductors would always have a ferrule (bootlace ferrule) crimped on first, or at a pinch, even soldered

Solder makes the problem worse. It will deform under pressure and make a loose connection even faster than the plain stranded copper would have done.

 

The Chinese are getting better at production, but as you found out, there is a big difference between mainland China and Taiwan, who I rate as very competent engineers. My heart sinks when I see PRC on the label.

So, true. Most Chinese stuffs never last as long as ones that are US or European made. Even nowadays the Taiwanese ones are becoming harder to find and getting replaced by Chinese ones quick. These ones are fine with small current drawing devices, but ones it goes to high wattage devices they just suck.

 

Guys, something that I always seen and made me curious about US made plugs and ones made in Asia is that the US made ones are made of brass and are flexible.

In fact these plugs are used on high wattage devices like the 1500W heater too but as it gets warm it becomes wobbly and flexible. So, had to snip and replace with a Leviton plug.

In the picture below the first cord is US made that I use with my PC CPU and its flexible just like most plugs that are US made. But in the second picture with grey cord that I have with the PC monitor is Asian made and is very sturdy and not flexible. Is there any particular reason why the US version is made this way? BTW its just a curious question.

 

It's why I said at a pinch. Some signal level conductors might have had a solder dip, but certainly not heavy duty stuff.
Even on the low voltage, low current boards, terminals with wire protection leaves would be specified/used.
On the better grade domestic stuff, you will get a ferrule termination, but I've seen plenty of soldered terminations as well.
I would agree about the flowing. Some "better" junction boxes have domed tips on the screw, but the really cheap ones will just have a crude squared-off end that simply graunches the conductor. There's a lot more to making up a cable than meets the eye

 

use this kind of switches without breaker and use these gauge wires and if u can search the wire of 7/29 in copper then that will be good for power cord

 

I don't know where "phil-s" gets this (bad word) about screw down terminals being unreliable. I have worked in the power industry for 30 years and have installed power circuitry for all power levels (some for 600 volt 2500 amp service!) and all of it uses screw down terminals of one type or other. I have removed equipment that was installed in the 40's that has been working for 50 or more years reliably with no fails due to terminals "loosening up" or any other fail like that. Properly rated screw terminals are completely reliable for use on copper wire, both stranded and solid. Better to look in the NEC code book rather than here for reliable information.
On your heater extension cord, simply buy a good quality plug and outlet and box and use a piece of #14 or #12 stranded cable, all of it available at Home Depot.
As others have mentioned, the weak place will be the wall socket in your home, which you do not have any idea on the quality of. Most now days use "push-in" connectors rather than screw terminals. NOT because of reliability but for ease and quick installation, which seems to be all that matters now to a contractor.
Run the heater for an hour at full power and then feel every part of the circuit for excess heat. Any more than slightly warm should be investigated to why.

 

use this kind of switches without breaker and use these gauge wires and if u can search the wire of 7/29 in copper then that will be good for power cord

Hi,
Here we use NEMA outlets. I've used 13ft 12AWG with a NEMA 5-20 outlet. Adding a switch here is kinda inconvinient because of the large size of a single switch in outlet box. Big and bulky unless I buy a power cord.

I've one question though, in the outlet that you have shown in the pic above does the outer cover act as a switch you meant?

 

I don't know where "phil-s" gets this (bad word) about screw down terminals being unreliable. I have worked in the power industry for 30 years and have installed power circuitry for all power levels (some for 600 volt 2500 amp service!) and all of it uses screw down terminals of one type or other. I have removed equipment that was installed in the 40's that has been working for 50 or more years reliably with no fails due to terminals "loosening up" or any other fail like that. Properly rated screw terminals are completely reliable for use on copper wire, both stranded and solid. Better to look in the NEC code book rather than here for reliable information.
On your heater extension cord, simply buy a good quality plug and outlet and box and use a piece of #14 or #12 stranded cable, all of it available at Home Depot.
As others have mentioned, the weak place will be the wall socket in your home, which you do not have any idea on the quality of. Most now days use "push-in" connectors rather than screw terminals. NOT because of reliability but for ease and quick installation, which seems to be all that matters now to a contractor.
Run the heater for an hour at full power and then feel every part of the circuit for excess heat. Any more than slightly warm should be investigated to why.

Hi,
I too have seen slight corrosion or oxidation on copper wires that are decades old but it doesn't affect the performance of the device or equipment much.
I've made a setup with #12AWG wire and it seems to be fine now. As for the outlet its a 20A hospital grade outlet(only for higher current draw ones) with required wiring. I had it installed for connecting higher powered devices in mind. Its holding fine.

 

WBahn
How lets see first off the cord has ohm value second there are now one new connection
I guess i should of worded that it makes a bigger load Pull more power that what causes the breaker to trip so if you have a 20 breaker you add cord to your 15 amp load now it now trips the breaker
Why one it's drawing more load ?
Two it causing more heat in the breaker to the load or
Three both I'll go with both.

Now I been a electrician for 34 year and this is what i have seen .
wall outlet been painted overloaded carbon builds up on contacts of outlet you plug a cheap cord most are 18 gauge heater 12 to 15 amps on high
cord cheap contacts start heating up more carbon build up. So yes it adds to it.

Next one of three things happen outlet burns out most time
cord end burns out sometimes
Last trips the breaker sometimes

Next case lot of people use long cords I've seen 100 feet with voltage drop of 40 volts on it cord nice a warm so yes it adds resistance.

I like this last one had a guy wouldn't believe it was this cord this on a job site 100 foot cord breaker bad nope breaker is good cord is bad
I told him that 20 amp is as big as you get for 120 outlet. Change the cord he waits till im gone changes breaker to a 40 amp using just one side
flips it on and the cord burnt from temp outlet box to his saw as soon as they turned it on LOL

 

As others have said, this is a dangerous setup. 1500W is the absolute design high limit of 14-gauge wire, and any electrician will tell you that to be safe the circuit has to have a margin for the expected load, so for a 1500W load, the wiring should be 12-gauge which can handle up to 2400 Watts. Note also that every connection, whether a plug and socket or wire-nut adds some resistance to the circuit, which is another reason that outlet strips are not recommended for high-power loads.

 

I disagree with the safety issues. If they were that unsafe it would be illegal to buy heater or anything that uses that wattage range of power.

Same with a electrician saying all electrical outlets are bad because that's what they see all day in their job. It's the same as a auto mechanic saying all vehicle are junk because that's what their job has the seeing every day.

I have ran heaters like this all my life and never had a major issue with outlets burning up from them. Usually if you have outlet going bad you know about it long before it has a problem simply because it doesn't hold onto plugs like a good condition one does.

As long as you do an initial check of your cord and connection points and don't find anything that seems suspicious after a hour or so of continuous use the odds are you are going to be just fine. I mean millions of these heaters exist and get used everywhere and yet actual problems with them and the outlets they are plugged into are extremely rare. Sort of like vehicle fires. Sure they happen, but everyone's vehicle doesn't burn down every time they go for a drive , do they?

BTW, 14 ga wiring is good for 18 amps in two active conductor circuits (IE single phase power) which at 120 VAC input is actually good for 2160 watts so, no. 1500 watts is not pushing it's current carrying limits. In fact is only 70% of it maximum rating and well under the industry standard of 80% of maximum rating for continuous duty use.

https://bethepro.com/wp-content/uploads/2015/11/extension-cords.pdf

https://www.stayonline.com/reference-circuit-ampacity.aspx

 

I had a home built with aluminum wiring. But the outlets were made for copper wiring. What a mess.
Most outlets were intermittent and looking at them showed the wire-holding screws on the outlets were burnt and the insulation on the wires near the screws was also burnt. The screws became loose because aluminum "creeps". Then new outlets were made for the aluminum wiring with larger heads on the screws. I replaced all outlets with the new ones and I tightened the screws as hard as I could. I was lucky that the wires were all long enough to have their burnt ends cut off.

 

@WBahn & @be80be

I have a partial theory that might explain your disagreement here about additional resistance causing breakers to trip. Unfortunately, it's a concept I've only ever vaguely understood, so I'm hoping you guys will recognize the underlying concept and set me straight.

Certain types of motors, and/or certain types of inductive loads, "want" to operate at a certain wattage. So, when provided the right voltage, they draw the intended amperage. However when provided lower voltage, they generate less back-EMF, so they appear as lower resistance and draw more amperage.

I'm sure I've gotten many of the specifics wrong, but I'm pretty sure there's some morsel of truth in there. If you guys could help clarify it for me, I'd appreciate it. In particular, I'm curious which situations this applies to: all inductors, motors only, only specific kinds of motors?

Anyway, assuming there's some truth to my claim above, then it would make sense that:

• A purely resistive load, like a space heater, will NOT draw more current when run on an undersized extension cord, and will NOT trip the breaker.
• A motor, like that in a circular saw, WILL draw more current when powered through a tiny cord with 40V drop, and therefore WILL trip an appropriately sized breaker.

I'm pretty sure that makes some kind of sense, but I'd love to hear what you guys think, because I'm still learning and you both know a lot more than me. Thanks!

 

tcmtech at post 33 so have i but i then so do I know what a good cord looks like and cheap one.
No if it's making good contact or not.

The poster said he has a 16 gauge cord that 13 amp cord here in the US you need a 12 or 14

Then theres the fact some so called 16 are not the 18
34 year's I've seen it all.

At ebeowulf17 you dead on it poor cords lower voltage more heat and a fire.

 

This is more like it

 

I had a home built with aluminum wiring. But the outlets were made for copper wiring. What a mess.

Hi,
Wouldn't the Aluminium and Copper have galvanic corrosion when joined together especially since it would be exposed to the moisture?

 

Hi,
Wouldn't the Aluminium and Copper have galvanic corrosion when joined together especially since it would be exposed to the moisture?

Yes if you don't make them up right they do. They made pigtails for them

 

Normally if you have a 15 amp circuit breaker (same for fuses), the 15 amps is for inrush so the breaker does not trip. But, for constant load your restricted to 12 amps. So, for your application you will need a 20 amp cable (12 AWG) and a 20 amp breaker. So remember for this situation (20A) you will have 20 amps for inrush and about 17 amps continuous loading. The extension cord with combination GFI and breaker would be very expensive. But, if you can plug into a 20 amp outlet (assuming it is protected by a 20 amp circuit breaker), then just get a 20 amp extension cord (make sure it is 12 AWG). 14 AWG - 15 amp rating : 12 AWG - 20 amp rating : 10 AWG - 30 amp rating assuming copper conductors!