AC systems (1) Except as otherwise provided for in this Code, ac systems shall be grounded if (b) the system incorporates a neutral conductor. 万一有UNBALANCED LOAD， NEUTRAL可能带电，然后DRYER带电。 万一POLE MOUNT TRANSFORMER 有CONTINGENCY, NEUTURAL也可能带电
SOME APPLICABLE CODES: (d) for the connection or replacement of dishwashers, cook tops, garburators, trash compactors, ovens, exhaust fans, baseboard heaters, furnaces, and hot water tanks, if the equipment installation work (iv) does not include installing, extending, altering, or repairing any electrical wiring connected to that equipment; and Electrical equipment ratings (2) Electrical equipment marked with both line-to-line and line-to-ground voltage ratings, such as 125/250 V, 120/240 V, 208Y/120 V, 480Y/277 V, or 600Y/347 V, shall be permitted to be connected only in a circuit that is solidly grounded and where (a) the nominal voltage of any conductor to ground does not exceed the lower of the two values of the equipment voltage rating; and (b) the nominal voltage between any two conductors does not exceed the higher value of the electrical equipment voltage rating. AC systems (1) Except as otherwise provided for in this Code, ac systems shall be grounded if (a) by so doing, their maximum voltage-to-ground does not exceed 150 V; or (b) the system incorporates a neutral conductor.
CONDO IS 3P4C FROM POLE, MOST SINGLE HOUSE IS USING 2P1N FOR COST REASON, CHEAP SOLUTION. US CODE ALLOWS BOTH 3P4C AND 2P1N EU IS ONLY FOR 3P4C BALANCE LOAD 的情况下， NEUTRAL 本身应该不带电。FOR UNBALANCED LOAD， NEUTRAL MAY CARRY CURRENT. (THIS IS WHY RANGE NEEDS DEDICATED CIRCUIT) NEUTRAL IS DESIGNED TO TAKE THE HIT. DESIGN PURPOSE IS DIFFRENT FROM GROUNDING. THAT IS WHY GROUNDING IS CALLED PE (PROTECTION EARTHING) OF COURSE, IN SOME CASES, NEUTRAL IS BONDED WITH PE. BUT FOR THE POLE MOUNT TRANSFORMER, THE TRANSFROMER IS NOT GROUNDED. FOUR WIRES ON POLE, L1, L2, L3 AND N. THE TRANSFORMER TAP IS BELIEVED TO BE CONNECTED TO N WIRE (DISTRIBUTION LINE). ALL CODES ARE FOCUSED ON ONE PURPOSE: SAFETY, ONLY SAFETY. SOME IDIOT LIKE TO CIRCUMVENT THE CODE, AND EXTEND TWO HOT WIRES FOR SMALL APPLIANCE, DISREGARDING SAFETY. RIDICULOUS. THERE IS A SAYING: YOU CAN NOT FIX STUPID.
CODES AND RULES ARE HERE FOR A REASON: BEHIND EACH SPECIFIC CLAUSE, THERE WAS A LIVE LOST OR BLOOD ON IT.
其实也不安全 TRANSFORMER INPUT SIDE PROTECTED BY UPSTREAM CB OUTPUT SIDE NO PROTECTION FROM DOWNSTREAM 而且，电器本身来说，220V的那种的保护和110V的保护等级设计是不同的。 220V的算0, 1类电器 （需要接地线， 所以也就是为了中国大陆的插座是3眼的原因） 110V的算2类电器 （不需要接地线，电器材料本身应该提供SUFFICIENT PROTECTION)
其实也不安全 TRANSFORMER INPUT SIDE PROTECTED BY UPSTREAM CB OUTPUT SIDE NO PROTECTION FROM DOWNSTREAM 而且，电器本身来说，220V的那种的保护和110V的保护等级设计是不同的。 220V的算2类电器 （需要接地线， 所以也就是为了中国大陆的插座是3眼的原因） 110V的算1类电器 （不需要接地线，电器材料本身应该提供SUFFICIENT PROTECTION)
交流电可以是其他波形，方波都有可能，只要ALTERNATIVE的都是。 180度相位差如何做到，如何保持 ALPHA怎么处理 结果就是， #1 不稳定的Vab, 噪声很大 #2 没有NEUTRAL， 触电的时候可能要死人的， 110V的CIRCUIT电流大一倍 #3 PHASE TO PHASE FAULT， FLASHOVER ENERGY USUALLY IS MUCH HIGHER. (FOR FLASHOVER, THINK ABOUT TESLA ON FIRE)
交流电可以是其他波形，方波都有可能，只要ALTERNATIVE的都是。 180度相位差如何做到，如何保持 ALPHA怎么处理 结果就是， #1 不稳定的Vab, 噪声很大 #2 没有NEUTRAL， 触电的时候可能要死人的， 110V的CIRCUIT电流大一倍 #3 PHASE TO PHASE FAULT， FLASHOVER ENERGY USUALLY IS MUCH HIGHER. (FOR FLASHOVER, THINK ABOUT TESLA ON FIRE)
Does the home have 220 volt service? If the home was recently built, the answer is almost always yes. Most houses today have two 110 volt wires and one neutral wire running into the house from the local distribution system. These wires can run underground or above ground.
Does the home have 220 volt service? If the home was recently built, the answer is almost always yes. Most houses today have two 110 volt wires and one neutral wire running into the house from the local distribution system. These wires can run underground or above ground. cintiman 发表于 2021-08-11 22:50
Does the home have 220 volt service? If the home was recently built, the answer is almost always yes. Of course, but it is 120/208 3PH. As long as the house is built after 1900, the answer is YES. Most houses today have two 110 volt wires and one neutral wire running into the house from the local distribution system. ALL Houses have 3PH IN, Phase to Phase 220, Phase to ground 110 These wires can run underground or above ground. Does NOT matter. What is the point here , Underground or Aerial?
回复 68楼cintiman的帖子 On the other hand, buildings that need low as well as high power in three phase and single phase are connected to the secondary of the distribution transformer. This way, they get a three phase Star connection (3-Phase, 4 Wire System with Neutral Wire). In the Star connection, Three Phase Line to Line (Phase to Phase) voltages are 400V AC (in US, 208V, 240V, 480V etc) and Single Phase Line to Neutral (Phase to Neutral), there are 230V AC (120V, 208V, 240V, 277V, 480V etc in the US).
FYI, RESIDENTIAL ELECTRICAL WORK IS VERY SHITTY. THAT IS WHY THOSE PPL DOING RESIDENTIAL ELECTRICAL WORK CAN NOT WORK FOR INDISTURAL CONSTRUCTION, OR CAN NOT FIND SUCH WORK PERIOD.
FYI, RESIDENTIAL ELECTRICAL WORK IS VERY SHITTY. THAT IS WHY THOSE PPL DOING RESIDENTIAL ELECTRICAL WORK CAN NOT WORK FOR INDISTURAL CONSTRUCTION, OR CAN NOT FIND SUCH WORK PERIOD. abracadabraa 发表于 2021-08-11 23:17
Not much you can do. Electrical code regulates safety only, don't have much to do with quality. Shitty work can still pass inspection. It is what it is. Just don't do crazy thing, or have weird idea: make 220V receptacle.
再说一遍，家里烘干机等大功率电器插座就是用两根3PH 110V合并的方式得到的，WITH NETURAL WIRE 安全性是没有问题的，因为这是你在家里可以得到220-240V电压的唯一方式，你别无选择 WITHOUT NETURAL WIRE, OR GROUNDING, IT IS FUUKED.
In electrical engineering, single-phase electric power is the distribution of alternating currentelectric power using a system in which all the voltages of the supply vary in unison. Single-phase distribution is used when loads are mostly lighting and heating, with few large electric motors. A single-phase supply connected to an alternating current electric motor does not produce a rotating magnetic field; single-phase motors need additional circuits for starting (capacitor start motor), and such motors are uncommon above 10 kW in rating. Because the voltage of a single phase system reaches a peak value twice in each cycle, the instantaneous power is not constant.[1] A single-phase load may be powered from a three-phase distribution transformer in two ways: by connection between one phase and neutral or by connection between two phases. These two give different voltages from a given supply. For example, on a 120/208 three-phase system, which is common in North America, the phase-to-neutral voltage is 120 volts and the phase-to-phase voltage is 208 volts. This allows single-phase lighting to be connected phase-to-neutral and three-phase motors to be connected to all three phases. This eliminates the need of a separate single phase transformer. Standard frequencies of single-phase power systems are either 50 or 60 Hz. Special single-phase traction power networks may operate at 16.67 Hz or other frequencies to power electric railways.[2]
🔥 最新回帖
AC systems (1) Except as otherwise provided for in this Code, ac systems shall be grounded if (b) the system incorporates a neutral conductor.
万一有UNBALANCED LOAD， NEUTRAL可能带电，然后DRYER带电。 万一POLE MOUNT TRANSFORMER 有CONTINGENCY, NEUTURAL也可能带电
我插个楼！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！
帮我解答一下！！！！！！！！！！！！！！！！！！！！！！！
dryer 回 breaker的电线只有三根线！！！！！！！！！！！！！！！！！ 我把黑线和白线接成了火线。 铜线改到neutral上了！！！！ 没有ground！！！！！！
请问大神！！！！！！！！！！！！ 这样行吗！！！！！！！
还是要以后把3线换成4线！！！！！？
目前运行了半年了没一点问题！！！！！！！！ 但是会不会又潜在的危险？？？？？？？？？？？ 拜谢！！！！！！！！！
(d) for the connection or replacement of dishwashers, cook tops, garburators, trash compactors, ovens, exhaust fans, baseboard heaters, furnaces, and hot water tanks, if the equipment installation work (iv) does not include installing, extending, altering, or repairing any electrical wiring connected to that equipment; and
Electrical equipment ratings (2) Electrical equipment marked with both line-to-line and line-to-ground voltage ratings, such as 125/250 V, 120/240 V, 208Y/120 V, 480Y/277 V, or 600Y/347 V, shall be permitted to be connected only in a circuit that is solidly grounded and where (a) the nominal voltage of any conductor to ground does not exceed the lower of the two values of the equipment voltage rating; and (b) the nominal voltage between any two conductors does not exceed the higher value of the electrical equipment voltage rating.
AC systems (1) Except as otherwise provided for in this Code, ac systems shall be grounded if (a) by so doing, their maximum voltage-to-ground does not exceed 150 V; or (b) the system incorporates a neutral conductor.
CONDO IS 3P4C FROM POLE, MOST SINGLE HOUSE IS USING 2P1N FOR COST REASON, CHEAP SOLUTION.
US CODE ALLOWS BOTH 3P4C AND 2P1N EU IS ONLY FOR 3P4C
BALANCE LOAD 的情况下， NEUTRAL 本身应该不带电。FOR UNBALANCED LOAD， NEUTRAL MAY CARRY CURRENT. (THIS IS WHY RANGE NEEDS DEDICATED CIRCUIT) NEUTRAL IS DESIGNED TO TAKE THE HIT. DESIGN PURPOSE IS DIFFRENT FROM GROUNDING. THAT IS WHY GROUNDING IS CALLED PE (PROTECTION EARTHING)
OF COURSE, IN SOME CASES, NEUTRAL IS BONDED WITH PE. BUT FOR THE POLE MOUNT TRANSFORMER, THE TRANSFROMER IS NOT GROUNDED. FOUR WIRES ON POLE, L1, L2, L3 AND N. THE TRANSFORMER TAP IS BELIEVED TO BE CONNECTED TO N WIRE (DISTRIBUTION LINE).
ALL CODES ARE FOCUSED ON ONE PURPOSE: SAFETY, ONLY SAFETY. SOME IDIOT LIKE TO CIRCUMVENT THE CODE, AND EXTEND TWO HOT WIRES FOR SMALL APPLIANCE, DISREGARDING SAFETY. RIDICULOUS. THERE IS A SAYING: YOU CAN NOT FIX STUPID.
CODES AND RULES ARE HERE FOR A REASON: BEHIND EACH SPECIFIC CLAUSE, THERE WAS A LIVE LOST OR BLOOD ON IT.
🛋️ 沙发板凳
technical 又handy的话，自己装一个。 要知道自己家电路怎么走的。
我就自己装了，不过太复杂的我不会。
淘宝淘个大功率的变压器就可以了，哪天心血来潮过了，收起来也方便。
显然是以前已经有了。。。每一个２２０Ｖ的ｏｕｔｌｅｔ都需要一个ｐｅｒｍｉｔ的。
装220v插头这个需要电工去看你家电箱计算你的用量会不会超过家用电要求，然后可能需要去City申请permit，电工安装好后会有inspector过来看一下。 这边的烘衣机、电车等等插头很多都是220v的，装插头不违法，把电路里面两个breaker并一下。
要按照国内的插头标准装大概不行，这边plugs没有那样的版面，有必要的话只能去买转接插头。
220VAC?
美国加拿大110-120V 日本 110V 法国 230V 。。。
你在哪里，阿富汗（220V）？
what about electrical shock hazard
step up transformer 110VAC/220VAC
当然可能。你自己装一个，没有permit，然后着火了烧死人，你可能会坐牢。
所以我说要technical 要知道你家电路怎么走的。
不过你说的也有点危言耸听了，有个东西叫breaker
不要，会失火
小家电是肯定可以用的，家用电器肯定都是进去之后交流变直流，只要电压够了就行。
你家有220V不代表没有permit，房子建的时候都申请好了。
你要新装一个就需要申请permit，这个几乎所有地方的housing code都要求。
不是每个outlet， 是每个breaker 要permit。 你去看你家电路面板里边如果已经有了， 只是连线出来, 是不需要permit，但是要另外增加一个220v的breaker 就需要permit。 一般家庭有dryer， wall oven， 电炉子，还有hottub的话， 就已经有了220v的breaker了。
但是不建议把220v的线连到普通的outlet上，是因为怕有人把110的电器插在上面出危险。 如果是小家电，只要个step up voltage converter就够了。
不需要吧？
:D 一会儿0 伏， 一会儿240V。。LIKE A ROLLER COASTER
搜transformer/ converter / adapter， 110v/220v ，
几十块钱吧。
即插即用，劳神子改装拉线干啥？！
谁说不需要电的设计，电是一定要提供图纸的。就算是卫生间，厨房装修这种小工程， power and lighting 的图都是要画出来的。 水和空调有的city可以as built。
其实也不安全
TRANSFORMER INPUT SIDE PROTECTED BY UPSTREAM CB OUTPUT SIDE NO PROTECTION FROM DOWNSTREAM
而且，电器本身来说，220V的那种的保护和110V的保护等级设计是不同的。
220V的算0, 1类电器 （需要接地线， 所以也就是为了中国大陆的插座是3眼的原因） 110V的算2类电器 （不需要接地线，电器材料本身应该提供SUFFICIENT PROTECTION)
可以装，你申请一个电的permit,再找个师傅来装就行了。还有如果你家的dryer 如果是用电的， 那大概率就240v的，你可以用那个插座用你的小家电。可能需要转接口。
把插座改220V（PHASE TO PHASE) 应该不符合CODE
不会。美国220V 电压的插头不一样，参考一些穿墙AC
怎么可能！我们家电炉子、烘干机都是220V 的 ， 要失火早就失火了！
美国插座也是三孔的呀
这边220V插口和110插口都不一样，110V插头插不进去
这接地线插孔不是为了小家电（2类电器）用的， 因为这类小家电不需要接地线。
这220V是靠变压器升压，而不是靠相位差得到的不稳定电压。
110V电器和220V的设计上对防火设计是不同的。
不会坐牢。就是没许可而已。1不安全，2被查会被罚。但你可以找有执照的电工装，你的box一般都有空slot，可以加，有可能要开墙走线。
这个不是相位差异吧，电压波形是一样的。 中国是220 sinX 正弦波，一根火线 美国220V需要两根火线，一根110V正弦波，然后第二根是110V差180度相位的正弦波，其实相对于第一根是相位相反的，就是-110的正弦波，合在一起，相对电压就是 110 sinX - 110 sin(X-180)=220 sinx 正弦波, 光看电压波形是一样的吧。
中国的220v电器插到美国的220V插座（插头不一样，要换过的）理论上都应该能够正常工作。
不用啊！从来没听说强制要有电图？ 最多建筑师简单的表示一下outlet在哪儿
交流电可以是其他波形，方波都有可能，只要ALTERNATIVE的都是。 180度相位差如何做到，如何保持 ALPHA怎么处理
结果就是， #1 不稳定的Vab, 噪声很大 #2 没有NEUTRAL， 触电的时候可能要死人的， 110V的CIRCUIT电流大一倍 #3 PHASE TO PHASE FAULT， FLASHOVER ENERGY USUALLY IS MUCH HIGHER. (FOR FLASHOVER, THINK ABOUT TESLA ON FIRE)
又安全隐患 为啥非的知法犯法
发电机出来的波形不会是方波的，难道变压器还能把电压波形给改了？ 180度相位差是电力公司电源提供的（中国的三相电是120度相位差） 安全隐患应该是没有的，这个又不是新发明，因为美国家里几乎所有大功率电器全是依靠这个220-240V电路工作的，比如空调、炉子、烤箱、烘干机等
多谢科普
赞，物理从来没学通过。电磁学还好点，力学搞不它清。美国好像是240V，不是220。我家换煤气炉，就不能用电炉的抽座，还好自己接个110不用开墙。
美国家庭的220V都是两根反相的110V得到的，美国电力入户就没有直接220v的
如果波形都是SINE的话，大家只需要买最SHITTY的UPS即可，何必买好的。
全世界的3相电都是120度相位差， 理论上是。不仅仅是中国。但这住宅的是单相线。电力公司电源提供180度的相位差，BY HOW? 我就想知道RESIDENTIAL的单相线怎么能做到差180度，而且保持。
如果非要从120/208 3相线拉，NEUTRAL线怎么办。 ELECTRICAL CODE是派什么用处的？
I DON'T THINK SO
3PHASE/4WIRE 120/208 FROM POLE
NOT TWO 1PHASE 120 REVERSED
Does the home have 220 volt service? If the home was recently built, the answer is almost always yes. Of course, but it is 120/208 3PH. As long as the house is built after 1900, the answer is YES.
Most houses today have two 110 volt wires and one neutral wire running into the house from the local distribution system. ALL Houses have 3PH IN, Phase to Phase 220, Phase to ground 110
These wires can run underground or above ground. Does NOT matter. What is the point here , Underground or Aerial?
On the other hand, buildings that need low as well as high power in three phase and single phase are connected to the secondary of the distribution transformer. This way, they get a three phase Star connection (3-Phase, 4 Wire System with Neutral Wire). In the Star connection, Three Phase Line to Line (Phase to Phase) voltages are 400V AC (in US, 208V, 240V, 480V etc) and Single Phase Line to Neutral (Phase to Neutral), there are 230V AC (120V, 208V, 240V, 277V, 480V etc in the US).
Three Phase Electrical Wiring Installation in Home - NEC & IEC (electricaltechnology.org)
MOST LIKELY VIOLATIING BUILDING/ELECTRICAL CODE.
SORRY, I DON'T GET TIME TO CHECK THE CODE FOR U.
1.电压问题，美国是单相120v，中国是单相220v。 2.频率问题，美国是60hz，中国是50hz。这才是主要的
你这个不是普通家庭用户，普通家庭只有两个110V火线，一根中性线入户，没有可能提供三相，只能靠两根火线，如果不是反相，不可能得到220V
我几年前建的新房，builder给我装的220V插座就是这样的，和其他烘干机和烤箱什么的都是一样接线，不可能有问题的
从3相线引出2根入户或者3根入户，都是STAR 3PH 进来的，(PS: 2根线相位差理论上是120DEG， 不是180).
所以2个火线弄出来220V IS UNSAFE, GOT IT?
FYI, RESIDENTIAL ELECTRICAL WORK IS VERY SHITTY.
THAT IS WHY THOSE PPL DOING RESIDENTIAL ELECTRICAL WORK CAN NOT WORK FOR INDISTURAL CONSTRUCTION, OR CAN NOT FIND SUCH WORK PERIOD.
那么，单项对地110V，两相电压就是110*1.732=190.52，那你是如何得到220V电压？
明白了，有什么办法可以降低风险？
DID I SAY 110/220?
I SAID 120/208, GO FIGURE
如果两根火线得到220v不安全，那么中国的三相电任何两相得到380v也是不安全的，一个道理
家庭是220-240V电压，没有208V的，
Not much you can do. Electrical code regulates safety only, don't have much to do with quality. Shitty work can still pass inspection.
It is what it is. Just don't do crazy thing, or have weird idea: make 220V receptacle.
I DON'T GIVE A ...ABOUT CHINA.
NEUTRAL WIRE, OR GROUNDING (NOT SAME FYI)
OK, ENOUGH BS.
WHAT IS CALLED RATED VOLTAGE, 120 +/- 3%.
ARE YOU IN CHINA? WHY YOU ARE SO ABSESSED ABOUT 220?
IT IS 120 SYSTEM IN US AND CANADA.
再说一遍，家里烘干机等大功率电器插座就是用两根110V合并的方式得到的，安全性是没有问题的，因为这是你在家里可以得到220-240V电压的唯一方式，你别无选择
再说一遍，家里烘干机等大功率电器插座就是用两根3PH 110V合并的方式得到的，WITH NETURAL WIRE 安全性是没有问题的，因为这是你在家里可以得到220-240V电压的唯一方式，你别无选择
WITHOUT NETURAL WIRE, OR GROUNDING, IT IS FUUKED.
骂人谁不会？ 家庭用电环境里，120V额定电压对应的是240V，110v对应220v，没有208V的额度电压
OMG
120 X 2^1/2 = 207.84
Single-phase electric power - Wikipedia
中性线当然有的
So what is your point, or pointsssssss
对，美国家庭用电只有120V/240V，208V是工业用电。可以参考我以前这个贴 https://forums.huaren.us/showtopic.html?forumid=398&topicid=2683008&postid=88240518#88240518
家庭用电只有120V/240V，208V是工业用电
NO
TYPICAL INDUSTRIAL: 5, 24, 48, 125, 270, 400, 690, 750...
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