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# USA Power and Voltages. What are the standard voltages for

USA Power and Voltages. What are...
USA Power and Voltages.
What are the standard voltages for households in USA + Canada.

I've heard that it's either 110, 115 or 120 Volts Single Phase.
And using the "Dual Voltage System" heavier loads can be 220, 230 or 240 Volts.
220 -230 - 240 across 2 Legs ( Phases )
Centre Tapped Transformer gets
110 - 115 -120
But is it 110 or 120 ?
I have an Air Conditioning Unit, that comes in 4 Models
120 Volts,
208 Volts
240 Volts
277 Volts.

OK this states 120 Volts which would be 1 Leg, 2 Legs 240 Volts.

But it appears that they have used 208 Volts previously.

Is 208 Volts and 277 Volts part of the 3 Phase System. ?

RCD's
Residual Current Devices,
Are they used in USA ?

RCBO's
Residual Current Devices with Overload Protection.
Are they used in the USA ?

Can you get a GFCI or CFP with Overload Protection
Ground Fault Circuit Interrupter
Ground Fault Protector

What's the difference between a Earth Leakage Circuit Breaker
and a GFCI or GFP
Show More
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9/24/2013
AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4,241
Experience: Contractor-42+ Years in the ElectricalTrade
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Welcome. My name is XXXXX XXXXX would be glad to assist.

1. USA Power and Voltages. What are the standard voltages for households in USA + Canada. I've heard that it's either 110, 115
or 120 Volts Single Phase. And using the "Dual Voltage System" heavier loads can be 220, 230 or 240 Volts. 220 -230 - 240
across 2 Legs ( Phases ) Centre Tapped Transformer gets 110 - 115 -120 But is it 110 or 120 ?

The standard voltage available in most parts of the country (US and Canada) is now nominally 120 VAC volts +/- 10%, and can
vary from 108 VAC to 132 VAC. It's usually around 117-118 VAC.

Transformers can vary on the output voltages, but as long as they are within the tolerance, it is acceptable
and will operate fine.
Homes and many businesses have 120/240 volt services which can supply both voltages

In the US and Canada, we use 240 volts which is 2 power phases of 120 volts (approx) each.
In other countries, where 240 is prevalent (or 230), they have one phase of power at 230 and a neutral on the other wire with the
2 wire connection.

2. I have an Air Conditioning Unit, that comes in 4 Models 120 Volts, 208 Volts 240 Volts 277 Volts. OK this states 120 Volts which would be 1 Leg, 2 Legs 240 Volts.
But it appears that they have used 208 Volts previously. Is 208 Volts and 277 Volts part of the 3 Phase System. ?

120 and 240 would be for residential mostly, where the 208 and 277 would be for commercial applications
where they do have 3 phase power, that is correct.

3.RCD's Residual Current Devices, Are they used in USA ?

RCD nor RCBO are used in the USA or Canada, we use the GFCI receptacles and GFCI breakers.

4. RCBO's Residual Current Devices with Overload Protection. Are they used in the USA ?
No , they are not used in the USA.

5. Can you get a GFCI or CFP with Overload Protection Ground Fault Circuit Interrupter Ground Fault Protector
US GFCI receptacles are for leakage only and operate like an RCD.
The GFCI circuit breaker does both, leakage and overload protection just like an RCBO.

6. What's the difference between a Earth Leakage Circuit Breaker and a GFCI or GFP
Essentially, they are the same.

RCD is the term normally used in countries other than the US and Canada, and the most common trip rating is 30ma though many other ratings exist.
A type RCD normally only protects against leakage to earth/ground, and does not protect against overload or short
circuit, a fuse or MCB must also be employed to protect against short circuit or overload.
A combined earth leakage and overload protective device is available, these are known as RCBOs.

Hope that explains the questions, please just reply if any clarification is needed.
Customer reply replied 4 years ago

Cool

So for an Air Conditioner in a 120 / 240 Volt Dual Voltage System,

I should select the 240 Volt Option, not the 208 Volt Option.

This would also apply to a Water Warmer.

120 / 240 Volt Dual Voltage System,

What do the Americian's call this system.

Can you give me a brand - part number as an example of a GFCI Circuit Breaker.

Also what is a good electrical wholesaler in the following area's

Atlanta

Washington DC

Galgary

3 Phase Power

What are the "Standard Voltages"

Phase to Phase

Phase to Neutral

1. So for an Air Conditioner in a 120 / 240 Volt Dual Voltage System,
I should select the 240 Volt Option, not the 208 Volt Option.
This would also apply to a Water Warmer.

Correct. Any air conditioning, water heating and appliance cooking is best at 240 volts.

The 240 volts will use less amperage than the 120 volt. Hence smaller
wires and breaker are needed.
It will use the same wattage no matter the voltage, but less strain in amperage on the service.
Amperage is determined by Watts/volts

2. 120 / 240 Volt Dual Voltage System,

What do the American's call this system.

It is 120/240 volt Single Phase

3. Can you give me a brand - part number as an example of a GFCI Circuit Breaker.
CLICK HERE and see one brand of GFCI breaker. There are many manufacturers and the panel at the location
determines which manufacturer to use.

3. Also what is a good electrical wholesaler in the following area's

Atlanta

Washington DC

Calgary

Most wholesalers require a licensed contractor to purchase electrical equipment.
Whereas, standard building supply stores will sell to both individuals and business.

There are many large chain stores such as Home Depot,Lowes and Menards, that can actually be priced as good
or better than the wholesalers because of the quantities they sell.
I purchase from them more than my wholesalers because of this reason. Costs!

There are so many wholesalers and they come and go, so as for each city it would be difficult
to list them all and be current. But a few of the larger ones are below.

AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4,241
Experience: Contractor-42+ Years in the ElectricalTrade
Verified
AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4,241
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Experience: Contractor-42+ Years in the ElectricalTrade

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