1875 watt hair dryer plugged into a 15 amp receptacle and circuit - WHAT?

[Telly]

I don't get it. Our 1500 watt decades-old hair dryer (some call them a "blow dryer") gave it up. Its motor speed became position-dependent. Performed a post-mortem on it. The brushes in its DC motor wore away. Had a diode bridge feeding it, to use a cheap DC motor on AC.

So buying a new hair dryer shouldn't be an issue, probably a zillion of them out there. But found something strange. Almost every hair dryer, except for a few small travel ones, now are 1875 watts, instead of 1500 watts, which used to be the standard max wattage.

I have an issue with a 1875 watt device, which would be the max power on high heat. 1875 watts at 120 volts is 15.625 amps. In addition, our line voltage is higher, usually 124-125 volts, which with a resistive load like a heating element, would result in a slightly higher current than that.

A regular outlet is rated at 15 amps. And usually the branch circuit feeding it is 14 gauge wire, 15 amps max rated. Often, 120 volt branch circuits in kitchens are 12 gauge 20 amp rated, but the outlets are 15 amp, idea being the max 20 amps branch capacity is spread over more than one 15 amp outlet.

A true 20 amp outlet can accept the typical 15 amp max plug, and also accepts the special 20 amp plug, which has its neutral prong at 90 degrees to the hot prong.

Obviously, the 1875 watt hair dryers have the regular 15 amp style plug. So on "High", they by definition overload the outlet itself, and if the branch circuit is sized for 15 amps, it too.

This overcurrent situation is not going to trip a breaker, as they require a higher current for a longer time to trip. Seems like a bad idea to me, eating into safety factor that has been the standard for years.

Am I missing something here? It makes no sense to me. Getting a new hair dryer rated 1875 watts, and telling DW not to use it on the highest heat, isn't a viable solution to me.

 

[SecondCor521]

I know just enough stuff about electricity to know that I don't really know stuff about electricity.

The plugs in my bathrooms near the countertops, where one of my kids uses a hair dryer, are all GFCI plugs. All three GFCI circuits in my breaker panel have 20 amp circuit breakers.

Maybe check the plug your wife would use and see if it's GFCI connected to a 20 amp circuit breaker? Seems like that would provide the safety factor you are seeking, at least to my uneducated view.

(The ordinary circuits in my house are 15 amp circuits.)

 

[Cortina]

I don't get it. Our 1500 watt decades-old hair dryer (some call them a "blow dryer") gave it up. Its motor speed became position-dependent. Performed a post-mortem on it. The brushes in its DC motor wore away. Had a diode bridge feeding it, to use a cheap DC motor on AC.

So buying a new hair dryer shouldn't be an issue, probably a zillion of them out there. But found something strange. Almost every hair dryer, except for a few small travel ones, now are 1875 watts, instead of 1500 watts, which used to be the standard max wattage.

I have an issue with a 1875 watt device, which would be the max power on high heat. 1875 watts at 120 volts is 15.625 amps. In addition, our line voltage is higher, usually 124-125 volts, which with a resistive load like a heating element, would result in a slightly higher current than that.

A regular outlet is rated at 15 amps. And usually the branch circuit feeding it is 14 gauge wire, 15 amps max rated. Often, 120 volt branch circuits in kitchens are 12 gauge 20 amp rated, but the outlets are 15 amp, idea being the max 20 amps branch capacity is spread over more than one 15 amp outlet.

A true 20 amp outlet can accept the typical 15 amp max plug, and also accepts the special 20 amp plug, which has its neutral prong at 90 degrees to the hot prong.

Obviously, the 1875 watt hair dryers have the regular 15 amp style plug. So on "High", they by definition overload the outlet itself, and if the branch circuit is sized for 15 amps, it too.

This overcurrent situation is not going to trip a breaker, as they require a higher current for a longer time to trip. Seems like a bad idea to me, eating into safety factor that has been the standard for years.

Am I missing something here? It makes no sense to me. Getting a new hair dryer rated 1875 watts, and telling DW not to use it on the highest heat, isn't a viable solution to me.

Nit Picking ... but if you voltage is higher , your current should be slightly lower ?? Am I missing something here . Your own sums say 15.625 amps at 120v , which agrees with me ... you can't have it both ways (higher current AND higher voltage). Solution move to the UK and get 240 volts approx ...... although with your logic , that might make the current higher too ??. Too early in morning for me !

 

[Marc]

I concur with your reasoning. I learned this the hard way. I put in under cabinet lighting/outlet system that has only 10amp plugs. Once one of the plugs burned out after using my coffee pot a few times, I researched all my kitchen plug in appliances. Coffee put and toaster (and air fryer which I gave away) are the only ones over 1200 watts. I will be replacing one with a 15amp plug directly wired to house wiring instead of light system.

I would check bathroom plugs for potential 20amp plug. If not, I would definitely talk your wife into a more efficient hair dryer. It won't necessarily fail first use but willl probably fail over time.

Marc

 

[JoeWras]

Blame the UL Standard, "UL 859" https://standards.globalspec.com/std/14550006/UL 859

Practically, wattage and amp draw is complicated. In EE school, I despised the Power course. It was a nightmare. Ohm's law is a start, but there's so much more to it, including some of the stuff going on inside the appliance, especially if it has a motor, like a hair dryer does.

I'll just say this: the UL standard was not something done willy-nilly. I'll leave it to the group of very smart EEs who approved this to the standards body. They knew well about about 14 gauge, 12 gauge wiring, and 15 and 20 amp circuits.

 

[latexman]

Just don't run it on HIGH.

 

[street]

Blame the UL Standard, "UL 859" https://standards.globalspec.com/std/14550006/UL 859

Practically, wattage and amp draw is complicated. In EE school, I despised the Power course. It was a nightmare. Ohm's law is a start, but there's so much more to it, including some of the stuff going on inside the appliance, especially if it has a motor, like a hair dryer does.

I'll just say this: the UL standard was not something done willy-nilly. I'll leave it to the group of very smart EEs who approved this to the standards body. They knew well about about 14 gauge, 12 gauge wiring, and 15 and 20 amp circuits.

I agree it really is a complicated and with so much more electric gadgets things get risky.

Being in the electric industry all my life I would say what SecondCor521 said. Make sure you have it on a GFI receptacle and on a 20 Amp circuit.

Over time what will happen with over loaded circuits the connections will start to break down and fatigue and cause failure. Connections would any other receptacles or wire that is cut and connected. A receptacle that is rated at 15 amps will break down also because the insulating capabilities won't be able to handle loads greater.

 

[Aerides]

Ok I might not know much about electricity but I do know hair dryers and hair.

High heat + High Speed, used concurrently for more than a minute or two, is a rare need. These new hair dryers are more flexible, have more settings, and and most women will use some combo of high/med/low, on speed and heat, but using high/high for more than a quick blast to get things started is a sure way to damage and fry your hair. This is not your 1980's hair dryer where the default was high-high.

But yeah, your bathroom should be on a GFI anyway.

Just don't run it on HIGH.

Not an option. Most of the time I want high heat, medium speed for the first minute or three. This avoids my hair frizzing while I dry it. Then I switch to med/med to finish up. Or even a cold blast that most devices also have.

 

[Irishgirlyc58]

I’m still trying to get over the fact that you took apart a very old hair dryer. [emoji23]
I don’t use one very often anymore and I have a cheap one just in case. It’s 1500 watts but honestly I’ve never paid any attention to the wattage of my hair dryer unless I’m buying a new one and then I would look for the highest wattage for a good price. I don’t think I’ve ever started a fire with one.

I checked Amazon and the Dyson hair dryer is 1600 watts.
Will that work?

 

[Aerides]

I checked Amazon and the Dyson hair dryer is 1600 watts.
Will that work?

Yeah but those start at $400 lol... (*and are totally worth it if you have difficult hair)

 

[skyking1]

Use the dryer. The circuit has a built in overload factor, as do the outlets. They just made a "Tim Taylor" more power grunt grunt biggest possible hair dryer that could be made.

 

[Irishgirlyc58]

Yeah but those start at $400 lol... (*and are totally worth it if you have difficult hair)

Right!
I have curly hair but it isn’t course so back in my younger days I would blow dry it straight.
If I was still doing that I would totally invest in a Dyson hairdryer.

I actually prefer my hair the natural curly way. Easier, cheaper. [emoji23]
But I totally understand the importance of a good hairdryer.

 

[djsander]

Look at the complete nameplate which will probably be 1875 watts at 125V. That will come out to 15 Amps. At that voltage and amperage your hair dryer is 8.33 ohms resistance. Now calculate the amperage at different higher or lower voltages based on that resistance. This will get you why you can use it on a 15 amp outlet. But nothing else should be operating. It gets more complicated with AC currents, but close enough. I maybe wrong, but that’s how they are designed in the US.

 

[Telly]

I looked back at my house breaker/gauge list, and verified by pulling off the outlet plate - I was mistaken, the circuit I have is 12 gauge 20 amp, not 14 gauge & 15 amp. The bathroom closest to the service panel has a GF! outlet, and the other two bathrooms wire through it.

Either way, plug-in devices into a regular outlet didn't exceed 1500 watts. At least that was the way it was for many years. I can't say I've seen a 20 amp plug on a corded consumer device. Maybe some window air conditioners might have it, but they could only be plugged into a 20 amp outlet. A 20 amp plug will NOT fit into a 15 amp outlet.

So a good safety margin existed for many many years. But now it seems to have gone by the wayside. Companies are involved in standards-setting. In the 1970s I was on a standards panel for a while. A lot of cat fighting between representatives for companies, and companies with whoever was leading it.

I hope that "well it's a hair dryer, no one's going to leave it on high for a long time" did not go into the decision making to raise the allowable power. Sounds like more of a marketing idea to get people to replace their dryers.

I found UL 859, but only abstracts are available free. And those really address the falling into the bathtub/shower/sink while plugged in issue (an inline GFI at the plug). It might not address the overall consumption.

About hair dryer power - It's pretty much a resistive load. Even though there is a small motor, its inductive effects are pretty much swamped out by the heating element. We have a foldable travel dryer, 1500 watts, on high heat high speed, using the Kill-O-Watt, measured the Power Factor as .99/1. Dropping down to lower heats, could get the PF to drop some (ie., become a little inductive).

With a resistive load, higher impressed voltage creates a higher current draw.

 

[SJhawkins]

I'm not with all my code books but 20amp bathroom circuits became code I think around the NEC 1996 cycle. Guess the hair dryer folks are upping the amps!

 

[ncbill]

Spec-built place here with a single 20A circuit for all three of my bathrooms.

First outlet in the master is GFCI.

 

[danwat1234]

Good news, an 1875w hair dryer does not necessarily actually use that much power. I have a kill-a-watt meter. I measured 3 different Con-Air branded ones with 1875w written on them. They all take about 1450w on high, 400w on low. [mod edit]
So it looks like 1875w, at least for the Conair brand is more marketing than truth.

 

[Qs Laptop]

Good news, an 1875w hair dryer does not necessarily actually use that much power. I have a kill-a-watt meter. I measured 3 different Con-Air branded ones with 1875w written on them. They all take about 1450w on high, 400w on low. [mod edit]
So it looks like 1875w, at least for the Conair brand is more marketing than truth.

And I will chime in and say my hair dryers are 1875 watts and I've been using them on a 15 amp circuit for 30 years with no problem.

(I do understand the concern though.)

 

[OldShooter]

UL is a very conservative organization and writes very conservative specifications. Assuming that hair dryer was approved by UL or ETL with a standard two-parallel-prong plug, then it is safe to plug into a 15 amp outlet.

Actually the much bigger risk is the plethora of electrical gadgets sold on the internet with either forged UL approval markings or no marks at all.

 

[RetMD21]

Good news, an 1875w hair dryer does not necessarily actually use that much power. I have a kill-a-watt meter. I measured 3 different Con-Air branded ones with 1875w written on them. They all take about 1450w on high, 400w on low. [mod edit]
So it looks like 1875w, at least for the Conair brand is more marketing than truth.

That's interesting. Probably people are looking for the most power and the new 1875 is really the old 1500.