larry dimock
Member
- Location
- Washington
Why aren't 1875 watt household hairdryers required to have their male cord end be the 20-amp configuration?
Hairdryers
- Thread starter larry dimock
- Start date
- Status
elec-student
Member
- Location
- Massachusetts
Re: Hairdryers
prob because most bathroom plugs arent designed that way and that ul probibly gave them a leaniancy
prob because most bathroom plugs arent designed that way and that ul probibly gave them a leaniancy
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Re: Hairdryers
Check the voltage rating on the label. The 1875W is a marketing ploy.
The dryer is usually 1875W @125V which equals 15A. This load is considered non-continuous so it can be fed by an OCPD rated at 100% of the load. Because the dryer is predominately a resistive load the current drawn decreases as the applied voltage decreases (about 14.4A at a normal 120V).
[ March 19, 2003, 05:52 PM: Message edited by: jim dungar ]
Check the voltage rating on the label. The 1875W is a marketing ploy.
The dryer is usually 1875W @125V which equals 15A. This load is considered non-continuous so it can be fed by an OCPD rated at 100% of the load. Because the dryer is predominately a resistive load the current drawn decreases as the applied voltage decreases (about 14.4A at a normal 120V).
[ March 19, 2003, 05:52 PM: Message edited by: jim dungar ]
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Hairdryers
Its similar to the 5 hp air compressors you can buy at the big box stores. Look at the single phase 120 v motor FLA table, its 56 amps. But wait...this is a miracle motor and produces 5 hp with a 15 amp cord cap! Actually if you look at the nameplate for HP it will say "special". HP can be determined by torque and these are not 5 hp motors.
Its similar to the 5 hp air compressors you can buy at the big box stores. Look at the single phase 120 v motor FLA table, its 56 amps. But wait...this is a miracle motor and produces 5 hp with a 15 amp cord cap! Actually if you look at the nameplate for HP it will say "special". HP can be determined by torque and these are not 5 hp motors.
bphgravity
Senior Member
- Location
- Florida
Re: Hairdryers
This is why it is so important to meet the requirements 210.11(C)(3). Bathrooms are rapidily becoming one of the heaviest loaded rooms in the home. It is a good design to dedicate a 20-amp circuit with 20-amp rated receptacles and to feed no other outlets, even if it is a single bathroom. This is certainly not required, but certainly meets the minimum and then provides what is really needed in todays bathrooms.
This is why it is so important to meet the requirements 210.11(C)(3). Bathrooms are rapidily becoming one of the heaviest loaded rooms in the home. It is a good design to dedicate a 20-amp circuit with 20-amp rated receptacles and to feed no other outlets, even if it is a single bathroom. This is certainly not required, but certainly meets the minimum and then provides what is really needed in todays bathrooms.
bphgravity
Senior Member
- Location
- Florida
Re: Hairdryers
Tom, I see a need for 20-amp rated receptacles, because of the extensive loads that are being placed on bathroom circuits. A circuit with a 20-amp rating and use of 15-amp receptacles are only allowed to be loaded to 12-amp per 210.21(B)(2) A 1850-watt hairdryer violates this. In most cases, it will not only be a hairdryer, but a curling iron, a shaver, and a half a dozen other items plugged into one plug. Place a 20-amp receptacle on the circuit, and at least you can load to 16-amp to cover pretty much any one load in the bathroom, and the receptacle terminals themselves don't become overloaded considering they are rated for the maximum rating of the circuit OCD.
Tom, I see a need for 20-amp rated receptacles, because of the extensive loads that are being placed on bathroom circuits. A circuit with a 20-amp rating and use of 15-amp receptacles are only allowed to be loaded to 12-amp per 210.21(B)(2) A 1850-watt hairdryer violates this. In most cases, it will not only be a hairdryer, but a curling iron, a shaver, and a half a dozen other items plugged into one plug. Place a 20-amp receptacle on the circuit, and at least you can load to 16-amp to cover pretty much any one load in the bathroom, and the receptacle terminals themselves don't become overloaded considering they are rated for the maximum rating of the circuit OCD.
- Location
- Massachusetts
Re: Hairdryers
210.21(B)(2) Allows 12 amps per 15 amp rated receptacle, a duplex is two receptacles.
I have my doubts that there is 1875 watt hair dryers. (Marketing BS)
Link to the Heat Gun Info.
210.21(B)(2) Allows 12 amps per 15 amp rated receptacle, a duplex is two receptacles.
I have my doubts that there is 1875 watt hair dryers. (Marketing BS)
Link to the Heat Gun Info.
bphgravity
Senior Member
- Location
- Florida
Re: Hairdryers
Regardless of what any one appliance may or may not draw, bathroom overloading is one of my number one service call issues. Again, as with many other topics on this forum, I cannot imagine why anyone would want to argue for the bare minimum. I am completely aware of what the code requires, and I think it isn't enough. The cost difference is minimal, it is not any harder to install a 20-amp rated recptacle, and will all is said and done, it is a better, safer, and definitly still compliant. I think one of the problems with our trade is that everyone is trying to learn and do the minimum. The attitude of "what can I get away with" or "do I have to since it isn't required" constitutes half of the topics on this forum. I teach and practice electrical fundementals and installations from the view point that the code is the starting point. Once I determine what SHALL be done and what MUST be done, I do and suggest on this forum, what SHOULD be done and what CAN be done. I am amazed how many qualified and skilled electricians really believe that doing it by the code minimum is actually a good job.
Regardless of what any one appliance may or may not draw, bathroom overloading is one of my number one service call issues. Again, as with many other topics on this forum, I cannot imagine why anyone would want to argue for the bare minimum. I am completely aware of what the code requires, and I think it isn't enough. The cost difference is minimal, it is not any harder to install a 20-amp rated recptacle, and will all is said and done, it is a better, safer, and definitly still compliant. I think one of the problems with our trade is that everyone is trying to learn and do the minimum. The attitude of "what can I get away with" or "do I have to since it isn't required" constitutes half of the topics on this forum. I teach and practice electrical fundementals and installations from the view point that the code is the starting point. Once I determine what SHALL be done and what MUST be done, I do and suggest on this forum, what SHOULD be done and what CAN be done. I am amazed how many qualified and skilled electricians really believe that doing it by the code minimum is actually a good job.
- Location
- Illinois
- Occupation
- retired electrician
Re: Hairdryers
bph,
Is the use of a 20 amp receptacle with a 15 amp plug really any safer that the use of the same load on a 15 amp receptacle? It appears that there is less surface area available to contact the grounded conductor blade of the 15 amp plug in the 20 amp receptacle than there is in the 15 amp receptacle.
Don
bph,
Is the use of a 20 amp receptacle with a 15 amp plug really any safer that the use of the same load on a 15 amp receptacle? It appears that there is less surface area available to contact the grounded conductor blade of the 15 amp plug in the 20 amp receptacle than there is in the 15 amp receptacle.
Don
bphgravity
Senior Member
- Location
- Florida
Re: Hairdryers
You Guys can pick apart anything that is suggested here, and that is your right to your opinion. I think it is a far stretch to suggest that attachment plug contact is compromised with the use of 20-amp rated receptacle. A 20-amp rated recptacle is listed and tested for use with 15-amp and 20-amp plug configurations. I have never, nor ever heard of any problems with this issue. Maybe you are using cheap and poorly manufactured recptacles?
You Guys can pick apart anything that is suggested here, and that is your right to your opinion. I think it is a far stretch to suggest that attachment plug contact is compromised with the use of 20-amp rated receptacle. A 20-amp rated recptacle is listed and tested for use with 15-amp and 20-amp plug configurations. I have never, nor ever heard of any problems with this issue. Maybe you are using cheap and poorly manufactured recptacles?
bphgravity
Senior Member
- Location
- Florida
Re: Hairdryers
On another note, it is not a code violation to use the "quick connect" hole terminals on the back of 15-amp receptacles. However, at least 80% of recptacle failure in my experience has come from this poor connection that either never completly clamped the conductor, or over time has lost its tight connection. 20-amp recptacles don't provide these terminations, and screw terminals must be used. I have actually seen electricians pigtail #14 wire off of the #12 wire to make this connection in bathrooms! At some point, you can become silly. I am not suggesting running #6 wire in 3" conduit to feed bathroom loads. One little upgrade is all I suggest, whats the harm in that?
On another note, it is not a code violation to use the "quick connect" hole terminals on the back of 15-amp receptacles. However, at least 80% of recptacle failure in my experience has come from this poor connection that either never completly clamped the conductor, or over time has lost its tight connection. 20-amp recptacles don't provide these terminations, and screw terminals must be used. I have actually seen electricians pigtail #14 wire off of the #12 wire to make this connection in bathrooms!
At some point, you can become silly. I am not suggesting running #6 wire in 3" conduit to feed bathroom loads. One little upgrade is all I suggest, whats the harm in that?
- Location
- Illinois
- Occupation
- retired electrician
Re: Hairdryers
bph,
I didn't say there was a problem, I just asked if they are really any safer than a 15 amp receptacle of the same quality when used with a 15 amp plug. I personally don't think that there is any difference in the safety of the 15 amp vs the 20 amp when using 15 amp plugs when comparing receptacles of the same quality. In some of the higher quality receptacles, the only difference between the 15 amp and 20 amp receptacle is the face, the guts are identical. As far as the push in connections, that would be a violation for the bathroom circuit as they are not permitted to be used with 20 amp wire.
Don
bph,
I didn't say there was a problem, I just asked if they are really any safer than a 15 amp receptacle of the same quality when used with a 15 amp plug. I personally don't think that there is any difference in the safety of the 15 amp vs the 20 amp when using 15 amp plugs when comparing receptacles of the same quality. In some of the higher quality receptacles, the only difference between the 15 amp and 20 amp receptacle is the face, the guts are identical. As far as the push in connections, that would be a violation for the bathroom circuit as they are not permitted to be used with 20 amp wire.
Don
- Location
- Massachusetts
Re: Hairdryers
BPH,
We are always free to go beyond code, and I do on a regular basis, it's easer when it is not you own money.
I know that when I post it is not a personal issue, and I think there are very few posts that are a personal attack. When I post I am so intent on getting my point out that I may forget about being polite.
This place would be pretty boring if we all agreed with each other.
[ March 24, 2003, 06:40 PM: Message edited by: iwire ]
BPH,
We are always free to go beyond code, and I do on a regular basis, it's easer when it is not you own money.
I know that when I post it is not a personal issue, and I think there are very few posts that are a personal attack. When I post I am so intent on getting my point out that I may forget about being polite.
This place would be pretty boring if we all agreed with each other.
[ March 24, 2003, 06:40 PM: Message edited by: iwire ]
electricmanscott
Senior Member
- Location
- Boston, MA
Re: Hairdryers
For a hairdryer that is running for ten minutes or so on a properly installed 15 amp receptacle I don't buy that there would be a problem. You'd think if this was such an issue houses would be burning all around us.
For a hairdryer that is running for ten minutes or so on a properly installed 15 amp receptacle I don't buy that there would be a problem. You'd think if this was such an issue houses would be burning all around us.
james wuebker
Senior Member
- Location
- Iowa
Re: Hairdryers
Good anwsers. So were talking about the min.in the code. When I'm wiring a house or what ever, I know all about what we now use in the bathroom, garage, kitchen & ect. I alway ask the customer if he or she would like more receptacles in these places. I explain the pros on adding more.I also let them know about the cons. If you have a larger bathroom (double sinks on one cabinet) I do put 2 separate circuits. A small half bath I'll put 1 in it. I run a 20 amp circuit a put in good 15 amp receptacles in there. I use GFCI receptacles or breakers at the main panel. Good topic. Bye
Good anwsers. So were talking about the min.in the code. When I'm wiring a house or what ever, I know all about what we now use in the bathroom, garage, kitchen & ect. I alway ask the customer if he or she would like more receptacles in these places. I explain the pros on adding more.I also let them know about the cons. If you have a larger bathroom (double sinks on one cabinet) I do put 2 separate circuits. A small half bath I'll put 1 in it. I run a 20 amp circuit a put in good 15 amp receptacles in there. I use GFCI receptacles or breakers at the main panel. Good topic. Bye
bphgravity
Senior Member
- Location
- Florida
Re: Hairdryers
Houses ARE burning all around us. 74,000 a year on average from electricity related alone. I am way behind many of you in experience and knowledge of this trade. I am honored to even be engaged by persons of such great expertise of NEC and electrical installations. I'm doing everything I can to keep up! It seems I keep ending up on the opposite side of an issue sometimes, and it gets me concerned that I might be missing something or that I am not understanding something correctly. I really thank all of you that have taught me more in the 2 months than I did my entire apprenticeship. I never mean any disrespect in my posts, and I hold most of you in the highest regard as true professionals and of course gentlemen.
Houses ARE burning all around us. 74,000 a year on average from electricity related alone. I am way behind many of you in experience and knowledge of this trade. I am honored to even be engaged by persons of such great expertise of NEC and electrical installations. I'm doing everything I can to keep up! It seems I keep ending up on the opposite side of an issue sometimes, and it gets me concerned that I might be missing something or that I am not understanding something correctly. I really thank all of you that have taught me more in the 2 months than I did my entire apprenticeship. I never mean any disrespect in my posts, and I hold most of you in the highest regard as true professionals and of course gentlemen.
Re: Hairdryers
bphgravity
The reason I asked about why you thought a twenty ampere rated receptacle was important was not to bust your chops. Perhaps we are saying different things when we say twenty ampere rated. During a presentation by a UL rep some years ago I asked if duplex receptacles could be relied on to carry twenty amperes when they are used as feed through receptacles with the entire circuit current flowing through the side screw bridge. He said that was how they were tested. I asked if that was true of the fifteen ampere pattern receptacles and he said yes. I took his word for it but I still don't know if I got the full story. So what I was looking for is does anyone have any authoritative information on what the labs test duplex receptacles to safely carry between the screw terminals. I would not want to install a twenty ampere pattern receptacle in a lavatory or bath out of concern that some heavy load will be plugged into it because it might be the only twenty ampere pattern receptacle in the house.
iwire
I have actually seen 1875 watt hair dryers. I encounter them on service calls after the breaker or fuse on an older general lighting circuit serving the bathroom has opened on overload. Customers are very surprised to find out that the device that can overload there circuit with only two or three more light bulbs on the circuit is even built. I was dubious about the current draw myself so I checked it with an amprobe. Those things actually draw the full fifteen amperes. I know that no one runs a hair dryer for three hours or more but that is still to much for my head. To my way of thinking any portable device that is meant to be supplied from receptacle outlets should be limited to 80% of the cord caps nominal pattern amperage. By that I mean any portable appliance that has a nema 5-15P cord cap should not draw any more than 1500 amps. On appliances like water coolers were the purpose of the cord and cap is to allow the plumbers to work on the thing without calling in an electrician I could understand being closer to the full current rating of the plug if the laboratory label said supply from a dedicated circuit.
--
Tom
bphgravity
The reason I asked about why you thought a twenty ampere rated receptacle was important was not to bust your chops. Perhaps we are saying different things when we say twenty ampere rated. During a presentation by a UL rep some years ago I asked if duplex receptacles could be relied on to carry twenty amperes when they are used as feed through receptacles with the entire circuit current flowing through the side screw bridge. He said that was how they were tested. I asked if that was true of the fifteen ampere pattern receptacles and he said yes. I took his word for it but I still don't know if I got the full story. So what I was looking for is does anyone have any authoritative information on what the labs test duplex receptacles to safely carry between the screw terminals. I would not want to install a twenty ampere pattern receptacle in a lavatory or bath out of concern that some heavy load will be plugged into it because it might be the only twenty ampere pattern receptacle in the house.
iwire
I have actually seen 1875 watt hair dryers. I encounter them on service calls after the breaker or fuse on an older general lighting circuit serving the bathroom has opened on overload. Customers are very surprised to find out that the device that can overload there circuit with only two or three more light bulbs on the circuit is even built. I was dubious about the current draw myself so I checked it with an amprobe. Those things actually draw the full fifteen amperes. I know that no one runs a hair dryer for three hours or more but that is still to much for my head. To my way of thinking any portable device that is meant to be supplied from receptacle outlets should be limited to 80% of the cord caps nominal pattern amperage. By that I mean any portable appliance that has a nema 5-15P cord cap should not draw any more than 1500 amps. On appliances like water coolers were the purpose of the cord and cap is to allow the plumbers to work on the thing without calling in an electrician I could understand being closer to the full current rating of the plug if the laboratory label said supply from a dedicated circuit.
--
Tom
- Status