Household Amperage: Typical Usage & Power

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Discussion Overview

The discussion revolves around the typical amperage supplied to households and industrial settings, exploring variations based on voltage and specific applications. Participants address both residential and industrial contexts, discussing standards, typical values, and the implications of different electrical setups.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • Some participants suggest that typical residential service amperage ranges from 150 to 200 amps, depending on the load.
  • Others note that the supply voltage significantly influences amperage, with most countries using voltages in the 220-240V range, while the US typically uses 240V.
  • There is a discussion about the variability in industrial amperage, with some stating that it can range from a few hundred to several thousand amps, depending on the application.
  • One participant mentions that a mid-sized electric arc furnace could have a transformer rated at 60 MVA, with secondary currents exceeding 44,000 amperes.
  • Some participants clarify that in the US, the nominal voltage is often referred to as 120V, with historical variations noted.
  • There is a debate regarding the amperage ratings of breakers, with some asserting that a two-pole breaker rated at 15A does not equate to 30A total, while others argue that 40A breakers are standard for larger household devices.
  • Several participants express uncertainty about whether the initial questions were homework-related, with mixed opinions on their vagueness.

Areas of Agreement / Disagreement

Participants generally do not reach consensus on the specifics of amperage ratings, particularly regarding breaker configurations and typical values for industrial applications. Multiple competing views remain on the topic.

Contextual Notes

Participants highlight the importance of regional differences in voltage standards and the variability in industrial requirements, which complicates the discussion of typical amperage values.

Who May Find This Useful

This discussion may be of interest to individuals studying electrical engineering, residential electrical systems, or those involved in industrial electrical applications.

Philosophaie
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What is the typical Amperage that comes into a normal household?
 
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Philosophaie said:
What is the typical Amperage that comes into a normal household?

Less than the service breaker rating. Most residential homes have around a 150-amp to 200-amp service. The load will depend on what is on in the house of course.

CS
 
Well it depends upon the supply voltage.

What is yours?
 
Studiot said:
Well it depends upon the supply voltage.
True, but AFAIK, most countries use similar supply voltages in the 220-240V range. The US uses 240V and typical amperages range from 40A for a small apartment to 200A for a medium-sized house.
 
How many amps tipically for an Industrial 3-phase Y and Delta?
 
Typical Amperage for 3-phase.
Supply to Demand:

Delta to Delta
Deltas to Y
Y to Delta
Y to Y
 
Philosophaie said:
How many amps tipically for an Industrial 3-phase Y and Delta?
There is no "typical" for industry since industrial requirements can vary by several orders of magnitude. You could see anything up to a few thousand amps at anything up to 13,200 volts. From a few kilowatts to a few dozen megawatts.
 
russ_watters said:
There is no "typical" for industry since industrial requirements can vary by several orders of magnitude. You could see anything up to a few thousand amps at anything up to 13,200 volts. From a few kilowatts to a few dozen megawatts.
You got me curious as I was thinking about http://en.wikipedia.org/wiki/Electric_arc_furnace" .
A mid-sized modern steelmaking furnace would have a transformer rated about 60,000,000 volt-amperes (60 MVA), with a secondary voltage between 400 and 900 volts and a secondary current in excess of 44,000 amperes.
 
Last edited by a moderator:
russ_watters said:
True, but AFAIK, most countries use similar supply voltages in the 220-240V range. The US uses 240V

Strange, I always thought it is 110/120V. That's why we here have problems with things bought in US.
 
  • #10
The US feeds street-level transformers with high line voltages, and the transformers knock the voltage down to 240V. The secondary coils are center-tapped to provide 120V to each of the two legs at the breaker panel. We only get 240V when loads are connected leg-to-leg, like electric ranges, clothes dryers, and submersible pumps.
 
  • #11
Yes 120volts would be nominal. But...
In the United States[3] and Canada[4], national standards specify that the nominal voltage at the source should be 120 V and allow a range of 114 to 126 V (-5% to +5%). Historically 110, 115 and 117 volts have been used at different times and places in North America. Main power is sometimes spoken of as 110; however, 120 is the nominal voltage.
http://en.wikipedia.org/wiki/Mains_electricity#Standardization"
 
Last edited by a moderator:
  • #12
In my first house (back in the 1970s) i had a problem with lights burning out very quickly. When I checked the line voltage it was 127.x VAC. When I switched to sylvania bulbs from the GE I was using they lasted almost twice as long... all I can think is that GE specs their lights at 110 and Sylvania specs them at a higher voltage.
It all depends on where you are on the grid as to what your actual voltage is.
 
  • #13
Borek said:
Strange, I always thought it is 110/120V. That's why we here have problems with things bought in US.
turbo-1 said:
The US feeds street-level transformers with high line voltages, and the transformers knock the voltage down to 240V. The secondary coils are center-tapped to provide 120V to each of the two legs at the breaker panel. We only get 240V when loads are connected leg-to-leg, like electric ranges, clothes dryers, and submersible pumps.
So that's 120V (or in special cases 240V) at the wall, but 240V at the main electrical panel. It's nice for flexibility.
 
  • #14
russ_watters said:
So that's 120V (or in special cases 240V) at the wall, but 240V at the main electrical panel. It's nice for flexibility.
And generally topped out at 200 amps design rating at the main panel and breaker box. In the US, we generally have 15 amp breakers, and in bridged (240 V) breakers the total amperage is 30 amps.
 
  • #15
turbo-1 said:
And generally topped out at 200 amps design rating at the main panel and breaker box. In the US, we generally have 15 amp breakers, and in bridged (240 V) breakers the total amperage is 30 amps.

Care to explain that?
 
  • #16
I think he's talking about a two-pole (so 240V) breaker being 15+15=30A. If so, it isn't correct. 15A times two poles is still just 15A. Nor is the typical amperage correct. 40A breakers are pretty standard for large household devices and you'll occasionally see 60A breakers.
 
  • #17
Looking at both the OP's questions together I wonder if this is homework?
 

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