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Electrical wire sizes & gauges vs Amps-ratings FAQs:
Questions & answers about electrical wire sizes, ampacity rating, run length, usage.
This article series gives Tables of Electrical Service Entry Cable Sizes, Electrical Circuit Wire Diameters, Circuit Ampacity, Allowable Voltage Drop, & Wire Size Increase based on Run Length assist in determining the electrical service size or other required electrical wire sizes at buildings.
These questions and answers about electrical wire sizes and servicve entry cable sizing were posted originally at SE CABLE SIZES vs AMPS - be sure to review that article.
On 2018-06-14 by (mod) - actual wire size measurement
You are so right
thank you for your careful reading I'll correct the text
On 2018-06-14 by Max
The SE CABLE SIZES vs AMPS article says the photo looks like "2.5 mm" wire, but it clearly looks like 1.5 mm.
On 2018-05-15 by (mod) - match wire size to amps loading for the circuit
Take a look at the data tag on your electric motor: find the voltage and the AMPERAGE that the motor requires. That will let you find the right wire size in the tables in this article series.
On 2018-05-15 by Magesh Kumar Srinivasan
For 7.5 HP Motor, 720 electrical wire is enough or what is to be used. please advice
On 2018-05-04 by (mod) -
No. 1 AWG copper
On 2018-04-28 by lee
what is the max size wire that will fit in a 100 amp breaker
On 2018-03-12 by Mike Burg
Can I use 2/0 aluminum service entrance cable for a small two family that has 100 amp panels for each unit?
On 2018-01-25 by (mod) -
The tables at AMPS & SEC SIZES note that using #10 copper you can run up to 200 ft. and be within acceptable voltage drop.
On 2018-01-25 by Dave
Need to run a direct burial line from a 200 amp box in my home out 200 ft to carport.at end I need one or 2 receptacles.this line is primarily for a 3 hp 26 amp motor to operate a car lift..my big concern is voltage drop..will use aluminum wire as I understand it is cheaper..in price thank you
On 2018-01-17 by Anonymous
What size wire and protection conduit can i use in 720.5 ampere?
On 2017-12-14 by saddiii
Total types of cables and wd current ratting
On 2017-10-02 by Brian
What size wire to use to hook up a 220 well pump at 150 ft
On 2017-06-25 by Anonymous
The table of voltage drops, is it in feet or metres?
On 2017-05-31 by (mod) - 2 conductors = 2 wires, probably 1 hot, 1 neutral
Thanks for asking, John as it helps me see where we need to clarify our text. But in this case I don't see the exact phrase you use
1 pair 16, 2 conductor 14
in our articles.
In general, in electrical talk,
2 conductors = 2 wires, probably 1 hot, 1 neutral
16 refers probably to the wire size or gauge - #16 or 16 gauge (which you wouldn't use for a residential 120VAC light or receptacle circuit)
15 probably refers to #14 or 14 gauge wire, typically used on a 15 amp circuit in buildings
On 2017-05-31 by John
Sorry, 1 pair 16, 2 conductor 14?
What does 1 pair 16, 2 conductor 4 mean?
On 2017-04-21 by Geoffrey
what size of the cable to use when connecting a 37kw machine?
On 2017-04-20 by Jon
I have a bell to install in a warehouse. It is 12v, .125A and needs to be 50' from the receiver.
What gauge wire should I be using?
On 2017-04-08 by (mod) - Dedicated Electrical Circuit
We call these, or the National Electric Code (for U.S. readers) calls these "Dedicated Electrical Circuits"
Heavy-usage appliances like an electric clothes dryer or water heater will have their own electrical circuit and breaker or fuse
Critical-use appliances, even though not using high wattage may also have their own circuit for reliability, such as refrigerators that we don't want going off because something else on the same circuit caused and overload.
Electrical expert Mike Holt and others point out that:
In the U.S. the National Electrical Code, since (I think) 1999, section 210.11(C)(2) requires one dedicated 20 amp branch circuit for receptacle outlets in the laundry area. This circuit is not dedicated for only the washing machine, all receptacle outlets installed in the laundry area can be on the laundry circuit.
GFCI (ground fault circuit interrupter) protection may also be required, e.g. for electrical receptacles near a laundry sink.
On 2017-04-08 by Terri
Do you have to have separate circuits for all house appliances like washer n dryer
On 2017-03-22 by (mod) -
Thanks for the question Amyan.
In one of the tables above I give actual "normal" diameter of various wire gauges.
One can sometimes see the wire gauge or size printed on the insluating jacket
One can guesstimate the wire gauge by the overall conductor dimension, but that's just approximate as insulation thicknesses vary depending on the wire type and rating.
One can also use a simple micrometer or measuring gauge to measure the thickness of the metal wire itself.
On 2017-03-22 04:02:13.709797 by Amyan
How do you find the diameter of wire
On 2017-03-17 15:24:09.490597 by (mod) -
Yep. We're a Two Harbors MN bunch ourselves.
On 2017-03-17 02:58:57.216113 by Mike white
Thank you. I figured I was good. Minnesota is throughout.
On 2017-03-16 16:40:19.069096 by (mod) -
That sounds right, Michael. The breaker in the panel is only protecting wiring that is "downstream" from that point. So the wire between the overhead or underground service point and the panel is, in effect, not protected by that breaker in any event. Using a larger diameter wire in that location than would be required by the panel ampacity is always safe.
On 2017-03-16 05:40:03.804719 by Michael White
I have a outdoor amusement concession trailer and I am changing the main breaker from 200 to 100amps can i get away with keeping the 3/0 125 ft .lead line and pass the electrical requirements for Minnesota's inspection.
On 2017-03-10 21:34:04.398565 by Martin
If I have a 600A incoming service...what would be the size of the conduit and the size of the wire and how many wires
On 2017-01-28 06:36:33.438383 by Joshua
What size of 4core amould cable is appropriate to install a 350kva 3phase generator at a 45meter distance.
On 2016-06-27 13:51:05.916490 by (mod) -
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On 2016-06-27 04:30:14.149759 by Mahboob
This is the good page & very helpfulness its need Down loaded page
On 2016-03-22 04:59:52.201083 by Alan Firby
I am trying to find out how much load that aerial aluminium 7/4.75 conductor is good for
On 2016-02-09 16:45:33.911946 by (mod) -
JD I've added tables and content to the article above to address increasing the wire size for long runs.
For an SEC, rather than simply applying the rule of thumb to increase the wire size for each 100 ft of run, I suggest that you need to consult an electrical engineer who will consider the voltage drop and specify the wire size. Otherwise your cost may be unnecesssarily high.
On 2016-02-09 by JD
What size wire do i need to run from a 200 amp pole service to a house 450 feet away?
On 2015-08-14 by paul
You produce a great information.
(Nov 23, 2015) Anonymous said:
In the wire size table below give the typical diameter of #14 copper wire as 2.05 to 2.32 mm or about 0.081 - 0.092 inches
Table reads .
#14 0.073- .064 / 1.84-1.
#12 0.092-0.081 / 2.32-
(Jan 27, 2016) Carl said:
I’m studying on my own to become a home inspector. With that said after trying to interpret what this article is trying to convey to me and I’m left a bit confused and hoping you could clear somethings up.
I get MAX AMP Allowed according a specific wire size for branched circuit wiring; however, what I’m confused about is the Service Conductor Wire sizes. Is it a separate set of wire/amp ratings then mentioned for the Max Amp Allowed for branched circuit wiring?
When comparing Service Conductor Wire Size with the fuses (or) breaker I’m getting confused.
Here’s an example of what I’m referring to:
(Service Conductor Wire Size)
100 AMP Breaker… (#4 copper wire) …. #2 Aluminum wire
(MAX AMP Allowed – Branched circuit wire sizes)
#4 Wire gauge… 70 amps (CU) … 45-50 amps (AL)
So, am I to read that as there has to be an additional 30 amps pushed through that wire before the breaker pops?
Wouldn’t the #4 wire burn out before the 100 amp rating of the breaker? This is where I’m getting confused.
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