Using higher amperage receptacles with lower amperage breakers

[Spork Schivago]

Re: Using higher amperage receptacles with lower amperage breakers

Usually it would be referred to as 12-2 w/ground, which would have black, white, and green/copper. 12-3 would generally have black, white, and red, as well as green/copper if grounded (12-3 w/ground).

Yes, that's what's confusing me. Is code 12-2 or is it actually 12-3? You're right dmill89, 12-2 has the white, black and green or copper, whereas 12-3 has the black, white, red and green or copper. I couldn't imagine 12-3 being required for 120VAC. I just don't see what you'd do with the red wire, unless you were wiring a 2 or 3-way switch or something.

[Spork Schivago]

Re: Using higher amperage receptacles with lower amperage breakers

I have seen it both ways. I once got 14-2 an had only that a black and white wire. Since then I have always looked for 14-3 and if ground is specified as also inclusive then I will look for 14-2 with ground. Also, I have seen 14-2 with ground be a bare ground wire and 14-3 having the ground wire with and green insulating coating.

This is what I've always called 12-2:
https://www.wireandcableyourway.com/...FY5WDQodUXkMHA

This is what I've always called 12-3:
https://www.wireandcableyourway.com/...FVNWDQodpXAD_A

I know back in the day, they had <whatever>-2 without the ground. I believe the proper way to say it is <whatever>-2 with ground or <whatever>-2 without ground or <whatever>-3 with ground or <whatever>-3 without ground. It's just now, most places I think carry the wires with ground, I think that's code. So I don't think most people specify the ground when talking about it. They just say I need some 12-2 or 12-3 or whatever.

I'm pretty sure just the black and white is <whatever>-2. The black and white with a green or bare copper wire is <whatever>-2 with ground. The black, white, red is <whatever>-3. The black, white, red, with green or bare copper is <whatever>-3 with ground.

[Spork Schivago]

Re: Using higher amperage receptacles with lower amperage breakers

I find NEC Article 210 Branch Circuits is saying "no" to a 20A receptacle on a 15A circuit. I don't see clauses differentiating residential or commercial buildings.
NEC maximum load on a circuit is 80% of the receptacle rating/circuit rating. So this would not be met. It's probably to prevent nuisance trips when running a 20A load, which a 20A receptacle invites on a 15A circuit.
There's no hazard with a 15A breaker as the limiting factor- it's just drama I think the standard is trying to avoid?

Note you can put a 15A (duplex) receptacle on a 20A circuit, and 50A receptacle on a 40A circuit.

Thanks redwire. I think with the NEC, the main differences between commercial and residential is the number of receptacle / switches per circuit, but I might be wrong. I don't know the NEC and I only used it for references. Thanks for looking into this and showing me there's no difference between residential / commercial for the amperage thing.

So it sounds like it's not allowed by code, but if I do have 14-2 in there, if the breaker is 15-amp, safety wise, I should be okay until I get a chance to upgrade it. If the breaker is rated for 20-amp and it's 14-2, than I'd have trouble because the wires would get too hot.

I'll check probably tomorrow or later today, after my wife wakes up from her nap and has a chance to watch the baby for a little bit. I got some stuff I'm doing on the PC and can't just go flipping breakers right away to figure out which one belongs to the bathroom.

[televizora]

Re: Using higher amperage receptacles with lower amperage breakers

Nothing bad will happen if you use higher amperage receptacles. If you overload the breaker, after some time(which depends of the characteristic curve - A, B or C) it will just shut down the circuit. There is no way to set something on fire, unless you have a faulty circuit breaker. But most of the time, when something has higher rated plug than usual - it needs additional juice to keep it running.
This problem is solved in Europe. We have only one type of sockets - Shucko - 16Amps/230V If something needs higher current than the rating of the Schuko socket - it is usually directly connected to the wiring using terminal blocks.
For portable loads with more than 16Amps requirement, we also have reinforced sockets - 25A/230V.
------
p.s Some technical stuff
First of all, when you design or modify electrical installation, you have to take into consideration the wire gauge(sq.mm) and to install such a circuit breaker, that there cannot be significant heating of the wire. Each wire gauge has rating for maximum constant current in amps.
Each wire is represented by it's Ohmic resistanse, which despite of it's low value is important. The maximum current is determined by this resistance which is determined by it's gauge
When the current is flowing across the wire, the wire heats up. This can be explained with Joule–Lenz law, Q= RI^2t, where Q is the amount of the electrical energy, transformed to heat.
Knowing this and the fact that most wires are insulated with PVC, we can conclude that the maximum current directly depends of the heat produced by the current and the heat released in the environment(which is depending of the method of the installation of the wire). The current must not produce significant heating of the wire or the heating must be below the maximum operating temperature of the wire, which is determined mostly by the type of the insulation used.
Knowing this we have to install circuit breakers in such a manner that these breakers will protect the wiring from faulty loads or overloads.

[Spork Schivago]

Re: Using higher amperage receptacles with lower amperage breakers

Thank you Televizora. So when current is flowing across any conductor, regardless of how much or what conductor, it will always produce some amount of heat? Even with traces on a circuit board?

From your formula, t is time?

Also, what type of terminal blocks do you guys use? I'm looking for some high quality high temperature terminal blocks, maybe ceramic. Something that can withstand maybe 2,000 degrees F, maybe 1,000 degrees F. Somewhere around there. I'm also okay with alternatives. I want something that functions real well but also looks real nice. Presentation means a bit too me with this other project I'm working on. Thanks!

[televizora]

Re: Using higher amperage receptacles with lower amperage breakers

Thank you Televizora. So when current is flowing across any conductor, regardless of how much or what conductor, it will always produce some amount of heat? Even with traces on a circuit board? From your formula, t is time?

There is no ideal conductor. Always some heat will be produced. And this heat will be proportional to the current flowing thru the wire.
But I have to notice that not only the heat is produced, but it's also dissipated to the environment. So, unless there is really high and inappropriate for the wire gauge current, you wouldn't notice very significant heating.
The only way for the insulation to melt is either very high current for one unit of time or constant overload that causes accumulation of heat that cannot be safely dissipated.
To understand what I say, just look at the wire as a heater.
If you look at the traces on a circuit board, you will notice that where a electronic component that generates high amount of heat is mounted, usually the trace is reinforced and wide - to dissipate heat.
We use two types of terminal blocks - screw type and spring type. The first is much older, the second type is mostly produced by Wago.
There is absolutely no need to use ceramic terminal blocks in household wiring. By the time the usual Bakelite block will be damaged, most likely the wires nearby will be already fried.
In our literature, what you call Joule heating is known as Joule-Lenz law/effect.
You use P=I^2.R, but we use representation with slightly different symbols - Q=I^2.R.t, to differentiate electrical power from amount of heat. Objectively speaking, the amount of heat is what is transformed to from electricity to work(or heat)... so it's electrical power..but...
The only difference between the usual wire and a heater resistor is the material they are made of, respectively the resistance. Usually the heater resistor is made of alloys with higher resistance per unit of length(in Europe we use meters and millimeters) But don't let yourself be fooled - any wire can become a glowing heater in the right conditions.
---
p.s In Europe we have 1 phase - 230V(220V). 3Phase - 400V(380V), with 120degrees offset between the phases.(in both cases line to earth voltage is 230V) where 1 phase(mono-phase power) is usually provided to multiple households by connecting each household to the same neutral, but to the different phases.
In Europe, where I live, we usually don't have 3 phase power, unless you specially request such for high power equipment. This is understandable, because the limit of one mono-phase account is 6/10/15kW. So unless you have a high power equipment/heating/high power tankless water heater you don't need 3 phase power.

[keeney123]

Re: Using higher amperage receptacles with lower amperage breakers

This is what I've always called 12-2:
https://www.wireandcableyourway.com/...FY5WDQodUXkMHA

This is what I've always called 12-3:
https://www.wireandcableyourway.com/...FVNWDQodpXAD_A

I know back in the day, they had <whatever>-2 without the ground. I believe the proper way to say it is <whatever>-2 with ground or <whatever>-2 without ground or <whatever>-3 with ground or <whatever>-3 without ground. It's just now, most places I think carry the wires with ground, I think that's code. So I don't think most people specify the ground when talking about it. They just say I need some 12-2 or 12-3 or whatever.I'm pretty sure just the black and white is <whatever>-2. The black and white with a green or bare copper wire is <whatever>-2 with ground. The black, white, red is <whatever>-3. The black, white, red, with green or bare copper is <whatever>-3 with ground.

So what I am saying is be aware that these rules may not hold true. There is always someone throwing a wrench in the gears. It is like the rules for color wires in houses are different for travel trailers. The rules for ground wire colors in Europe and the US may be different. They specify chassis ground with green and a yellow stripe where that is not require here.

[televizora]

Re: Using higher amperage receptacles with lower amperage breakers

The rules for ground wire colors in Europe and the US may be different.

The new color standard here defines:
- Blue as Neutral
- Green/Yellow as Protective Earth
- Brown as Live/Line
For 3 phases:
- Brown - First Phase
- Black - Second Phase
- Gray - Third Phase
- Blue - Neutral
- Green/Yellow - Protective Earth
Also:
We have standard cross sections for the wires(you know this as gauge)
For 230V electrical installations these are wire cross sections:
Used for lighting appliances:
1mm2 - max 10A
1.5mm2 - max 16A
---
Power sockets
2.5mm2 - max 25A/nominal 16A with Schuko sockets and 16A circuit breaker
4mm2 - max 32A - usually used with 25A reinforced sockets and 25A circuit breaker. Can be used with 32A circuit breaker with appropriate load connected via terminal blocks
---
6mm2 - max 50A
10mm2 - max 63A
Usually 6mm2 or 10mm2 enters the house and it's used to connect the house/apartment to the electrical grid. Also often used for high power loads like tankless water heaters.
Powerful electric cookers, high power heating or tankless water heaters(10+ kW) are usually connected via 3 phase power lines.
---
p.s It's much simpler when such things are standardized.

[delaware74b]

Re: Using higher amperage receptacles with lower amperage breakers

Spork - the GFCI needs to be replaced. The newer GFCI's have better surge protection. Your existing one is tripping from inductive kickback from the fan motor. My sister had one that did the same thing in her house. I replaced it and no more problems.

Building wire (Romex, MC cable, etc) is designated as 2 conductor (black, white, green or bare), 3 conductor (black, red, white, green or bare). The color codes can be special ordered for different voltages (brown, gray, green for 277volt systems).

The NEC has no color code standards except for: gray or white designating a grounded (neutral) conductor, green designating a grounding conductor. I hate the legaleze terminology the NEC uses. The accepted color codes for hot conductors are: black and red for 120/240 single phase, black, red, blue for 120/208 3-phase, orange is used to designate a 'high leg' for older corner/open delta systems where it is 208 volts to ground in a panel with 120 volts to ground. It gets more confusing with 277/480 systems. Brown, orange, yellow are hots while gray or white is the neutral. There is a discussion within the NEC to replace the guidelines for the 'b' phase color code to be changed to purple from orange. It doesn't address the existing installations currently in use. Also, it is common to have both 277/480 AND 120/208 3-phase systems in use at the same time in commercial and industrial locations. I have seen same colors used for both systems in the same building and junction boxes not labelled for the contained voltages.

[Spork Schivago]

Re: Using higher amperage receptacles with lower amperage breakers

Spork - the GFCI needs to be replaced. The newer GFCI's have better surge protection. Your existing one is tripping from inductive kickback from the fan motor. My sister had one that did the same thing in her house. I replaced it and no more problems.

Building wire (Romex, MC cable, etc) is designated as 2 conductor (black, white, green or bare), 3 conductor (black, red, white, green or bare). The color codes can be special ordered for different voltages (brown, gray, green for 277volt systems).

The NEC has no color code standards except for: gray or white designating a grounded (neutral) conductor, green designating a grounding conductor. I hate the legaleze terminology the NEC uses. The accepted color codes for hot conductors are: black and red for 120/240 single phase, black, red, blue for 120/208 3-phase, orange is used to designate a 'high leg' for older corner/open delta systems where it is 208 volts to ground in a panel with 120 volts to ground. It gets more confusing with 277/480 systems. Brown, orange, yellow are hots while gray or white is the neutral. There is a discussion within the NEC to replace the guidelines for the 'b' phase color code to be changed to purple from orange. It doesn't address the existing installations currently in use. Also, it is common to have both 277/480 AND 120/208 3-phase systems in use at the same time in commercial and industrial locations. I have seen same colors used for both systems in the same building and junction boxes not labelled for the contained voltages.

At the old house, I had to hook up a special 240V outlet for a device I have. I didn't know enough about 240V at the time and went for 12-2 instead of 12-3. In this house, I'll use 12-3. Anyway, I remember I had to put black electrical tape on the white wire at both ends (the receptacle and the breaker). I think that was code, to let other people know it was hot.

Anyway, I'd like to thank everyone for their help. Hopefully later today I get it hooked up. My wife went back to work and now I get to wake up really early with the baby and take care of her all day. When she comes home from work, because she's still not used to the schedule, she usually falls asleep and I get to watch the baby all day. It's hard to get work done right now.

I still gotta figure out why the fan still runs after the GFCI outlet trips. I'm pretty sure it's just hooked to the GFCI outlet incorrectly.

[keeney123]

Re: Using higher amperage receptacles with lower amperage breakers

The new color standard here defines:
- Blue as Neutral
- Green/Yellow as Protective Earth
- Brown as Live/Line
For 3 phases:
- Brown - First Phase
- Black - Second Phase
- Gray - Third Phase
- Blue - Neutral
- Green/Yellow - Protective Earth
Also:
We have standard cross sections for the wires(you know this as gauge)
For 230V electrical installations these are wire cross sections:
Used for lighting appliances:
1mm2 - max 10A
1.5mm2 - max 16A
---
Power sockets
2.5mm2 - max 25A/nominal 16A with Schuko sockets and 16A circuit breaker
4mm2 - max 32A - usually used with 25A reinforced sockets and 25A circuit breaker. Can be used with 32A circuit breaker with appropriate load connected via terminal blocks
---
6mm2 - max 50A
10mm2 - max 63A
Usually 6mm2 or 10mm2 enters the house and it's used to connect the house/apartment to the electrical grid. Also often used for high power loads like tankless water heaters.
Powerful electric cookers, high power heating or tankless water heaters(10+ kW) are usually connected via 3 phase power lines.
---
p.s It's much simpler when such things are standardized.

So you do not distinguish earth ground from chassis ground. When I work for Langley Ford Instruments in 1986 we had to put in the green and yellow stripe wire for chassis ground and then come off of that with a green wire that went to earth ground on the units that were sold in Europe.

It would be easier if everyone could agree to a standard unfortunately people can not. I wish people could agree on metric as a standard of measurement. It seems that will never happen.

[keeney123]

Re: Using higher amperage receptacles with lower amperage breakers

At the old house, I had to hook up a special 240V outlet for a device I have. I didn't know enough about 240V at the time and went for 12-2 instead of 12-3. In this house, I'll use 12-3. Anyway, I remember I had to put black electrical tape on the white wire at both ends (the receptacle and the breaker). I think that was code, to let other people know it was hot.

Anyway, I'd like to thank everyone for their help. Hopefully later today I get it hooked up. My wife went back to work and now I get to wake up really early with the baby and take care of her all day. When she comes home from work, because she's still not used to the schedule, she usually falls asleep and I get to watch the baby all day. It's hard to get work done right now.

I still gotta figure out why the fan still runs after the GFCI outlet trips. I'm pretty sure it's just hooked to the GFCI outlet incorrectly.

I also found out from my nephew that the new GFCI have a connection that you can put the wire in the back of the receptacle and when you tighten the screw on the side it tightens like a foot down on the wire inside the receptacle. This is unlike the old design that one just pushed it in and it relied on spring tension to contact a small surface.

[stj]

Re: Using higher amperage receptacles with lower amperage breakers

the leaf springs are dangerous, the only ones approved these days have multiple springs layered in a metal shell,
so you have multiple contact points etc.

[keeney123]

Re: Using higher amperage receptacles with lower amperage breakers

the leaf springs are dangerous, the only ones approved these days have multiple springs layered in a metal shell,
so you have multiple contact points etc.

These new ones do not have the springs they actually use the screw to tighten down on the wire. The wire is inserted in the back like the old spring ones, but the new ones you can just pull the wire back out. To tighten you use the screw on the side. The same screw one would wrap the wire around. I am not sure the internal design. I would image it is like on a electrical panel that has a foot at the bottom of the screw that compresses the wire as it is tightened. So I found this site on the differences. You just need to translate from French. http://roulezelectrique.com/la-diffe...x-prises-120v/

[stj]

Re: Using higher amperage receptacles with lower amperage breakers

that link is actually pretty funny.
the fact you have different grades of something that could cause a fire!!

in europe, there is only 1 grade - the safe and well built one - regardless of end cost.

[dmill89]

Re: Using higher amperage receptacles with lower amperage breakers

that link is actually pretty funny.
the fact you have different grades of something that could cause a fire!!

Yes, and the cheapest grade is absolute garbage (what do you expect for $0.69), not only are the "quick-wire" spring clamps a potential fire-hazard the contacts are poor and will wear out in just a few years even with just normal residential use leading to loose plugs (also a potential fire hazard) and requiring replacement. While you don't need to necessarily go with "industrial" grade outlets just moving up a step or two from the $0.69 ea. ones to the $2-$3 ea. "premium/preferred" residential ones makes a big difference in quality (and safety).

Unfortunately the $0.69 garbage ones are what just about every contractor puts in new houses unless you specifically spec. (and pay for) upgraded ones, saving a buck or two per outlet adds up when they're building hundreds or thousands of houses a year (as many big contractors are), and even the cheapest outlets will typically last until the standard 2-3 year new home warranty expires (though just barely).

[delaware74b]

Re: Using higher amperage receptacles with lower amperage breakers

The screw-clamp connections on GFCI's are good. You can still side-wire but not needed. The connections are a square metal plate with grooves to hold the wire. The plate is also threaded for the screw. This design actually started on the industrial/hospital spec-grade devices. They accept solid or stranded wire with no issues.

RANT: The 'back-stab' devices are pure junk. The only thing they're good for is service calls and burnt wiring. Both my boss and I refuse to use them, even if it's in the job specs. I have seen only 1 device burnt up using the side wiring and it was caused by the wire looped backwards on the screw. (End rant)

All the devices in my house were actually 'back-stab' only devices(modular house built in 1989). All are being replaced, 1 room at a time, with spec-grade devices. Also, all replacements are being pig-tailed were there is more than 1 set of wires in the box. I can replace the device later without breaking the circuit or turning off the breaker.

[televizora]

Re: Using higher amperage receptacles with lower amperage breakers

So you do not distinguish earth ground from chassis ground.

In many scenarios, in Europe chassis is connected to the earth.
Our neutral is also connected to the earth. The most widely used grounding system is TN.
There is absolutely no problem for us to have chassis ground, but we call this "floating ground", because conditionally it's "ground for the chassis" but it could have more potential to the Earth than zero.
Most of the times, our equipment chassis is connected to the Earth, because of safety requirements. We have double the voltage you have.
About metrics - the metrics surpass imperial units, because you can easily convert between derivative units. In the metric system the prefix tells you the magnitude - how big something is or how small it is. So you don't need to know thousands of different irregular units like foot, inch, grain, pound and etc.
I asked multiple times people from USA and UK - how they convert between the different units - a conversion that usually ends with some irregular fractions. Seems that even the people in USA have difficulties converting from one unit to yet another.

... not only are the "quick-wire" spring clamps a potential fire-hazard the contacts are poor and will wear out in just a few years even with just normal residential use...

In our country no dangerous electric equipment will ever pass approval. We even have special committee that deals with this kind of stuff(not very effectively thou)
But you have to notice that there are spring-type terminal blocks like Wago that are rated for as high as 32Amps. So the problem is not the quick-wire connection, but the poor quality.
p.s Our junction boxes are plastic, not metal. Also our outlet boxes are plastic, so the safety problem with yours is not applicable in Europe. Just imagine what could happen if when you are pulling the wires tru the the openings of the box, you damage the insulation and when you install the power socket, you connect the ground(the whole box is metal and grounded) with line voltage. This is fire hazard.

[Spork Schivago]

Re: Using higher amperage receptacles with lower amperage breakers

I also found out from my nephew that the new GFCI have a connection that you can put the wire in the back of the receptacle and when you tighten the screw on the side it tightens like a foot down on the wire inside the receptacle. This is unlike the old design that one just pushed it in and it relied on spring tension to contact a small surface.

Isn't that called back stabbing and isn't that a bad idea? I planned on just using the screw terminals and wrapping it around and tightening them down. I heard some bad stuff about backstabbing and believe it should be avoided, unless things have changed. From the sounds of it, things have changed a bit, but does it actually make a difference? Is it a good idea to backstab now? Thanks!

[Spork Schivago]

Re: Using higher amperage receptacles with lower amperage breakers

The screw-clamp connections on GFCI's are good. You can still side-wire but not needed. The connections are a square metal plate with grooves to hold the wire. The plate is also threaded for the screw. This design actually started on the industrial/hospital spec-grade devices. They accept solid or stranded wire with no issues.

Are you saying it's okay to back-stab with the GFCI outlets?

...Also, all replacements are being pig-tailed were there is more than 1 set of wires in the box. I can replace the device later without breaking the circuit or turning off the breaker.

Could you go into a little more detail about this? When you say if there's more than 1 set of wires in the box, you mean if the receptacle / switch is daisy chained, right? What wires do you pig-tail? I'd like to see a pic or something. It'd be nice to be able to replace the switches / receptacles without having to flip the breaker.

Thanks!