I am wondering which number I should use for a voltage drop for AWG 16 (round trip) per meter per ampere ?

I need to take bit more practical approximation here in calculation. We will have 5 A current running in 5 meter long wires (1 x power and 1 x ground).

 

I am wondering which number I should use for a voltage drop for AWG 16 (round trip) per meter per ampere ?

I need to take bit more practical approximation here in calculation. We will have 5 A current running in 5 meter long wires (1 x power and 1 x ground).

There are plenty of charts of resistance per meter by wire gauge.

Get the Ohms/meter for 16AWG from the chart.

Multiply by 10 to get the resistance of 10m.

Multiply that by 5 to get the voltage drop at 5A.

 

16AWG pure copper is 13.2 ohms/km, or 13.2mOhms/m.

Is this DC or AC ?

But most wire isn't pure copper as that would be too soft to be practical. Also could be copper-coated aluminium. which has a higher DC resistance.

 

No AC only DC power supply cables.

Resistance 13.2 mOhms/meter means that for 5 meter round trip I need to multiply by 2 x 5 = 10 and for 5 A I need to multiply by 5.

Drop = 13.2 /1000 * 10 * 5 = 0.66V

 

Is this DC or AC ?

What difference does that make regarding the OP's question?

 

What difference does that make regarding the OP's question?

Not much over 5m, but I recall somewhere there is a factor for one or the other over a certain distance.

Again, not relevant for 5m, is that cables in conduit get warm and this increases resistance, so there is a derating for that.

 

There is another thing to consider, in addition to the actual conductor resistance, which often is a bigger problem. That is connection resistance , because that is the unknown factor.

 

DC is more efficient for power transmission.

Is AC or DC More Efficient? The Answer Varies - ScienceInsights

 

DC is more efficient for power transmission.

Is AC or DC More Efficient? The Answer Varies - ScienceInsights

The answer is "YES", with the qualifier being "It Depends".
CERTAINLY DC IS more efficient for transmission. But mostly, POWER is used by multiple users, and so DISTRIBUTION is required. In most cases, distribution to a number of users is more efficient using AC.
The result is that TRADE-OFFs are usually required. AND, exactly like the past conversations, "It Depends".

 

If it is a TRI-RATED 16AWG cable then it also has to pass the British Standard for a 1.5mm2 cable (BS6231) which cross references BS6360, which specifies the cable by its resistance not its measured cross sectional area. (So you can't call it a 1.5mm^2 copper cable unless it meets the resistance requirements regardless of its measured cross sectional area, sensible in some respects, but slightly absurd in others.)
So a TRI-RATED 16AWG cable must be <12.1Ω/km at 20°C for a plain copper conductor.

 

Of course, the acceptable voltage drop will depend a whole lot on the application, which we have no clues about. If the load is an electric space-heater the voltage drop will not have a noticable effect, but if it is powering a color television set the voltage drop might matter more.
An electric 120 volt power handsaw will be OK with 100 feet of #16 extensio cord, but a 25 watt output radio transciever will not work so well with the 12 volt feed thru the same extension cord. (Personal experience verifies this)

 

you can use power supply with feedback to compensate for voltage drop. this requires additional wires though they can be much thinner since only used for voltage feedback (very low current). this way you get 12V (or whatever you use) at the load... regardless if wires from PSU to load are 5m or 5cm long.

 

Post #12 sounds a whole lot like remote sensing on a regulated power supply. Available on a few brands of supplies back in the 1960's era, much more common today.

 

16AWG pure copper is 13.2 ohms/km, or 13.2mOhms/m.

Is this DC or AC ?

But most wire isn't pure copper as that would be too soft to be practical. Also could be copper-coated aluminium. which has a higher DC resistance.

Not true. Almost all commercially available copper wire is 99.95% or higher pure copper, the rest being cuprous oxide and other metallic imputities. The issue of copper wire purity has been a "fool's gold" scam among the audio sound system purists (audiophiles) for many years. I remember that some years ago, Mouser (a major electronic component distributor in the USA) was selling a $2.95 USD duplex wall receptacle for about $130 USD (after all, it had gold plated contacts)!
The audiophile crowd cries that the additional 0.02% - 0.04% purity of Oxygen-Free Copper (OFC) makes a magical, unbelievable difference in the sound of their 33-1/3 RPM vinyl records. But, that's a debate for another forum. Please don't take this as a challenge to start one.
Read a good explanation on the subject at https://www.copper.org/resources/properties/microstructure/coppers.html
Cheers,
DaveM

 

Not true. Almost all commercially available copper wire is 99.95% or higher pure copper, the rest being cuprous oxide and other metallic imputities. The issue of copper wire purity has been a "fool's gold" scam among the audio sound system purists (audiophiles) for many years. I remember that some years ago, Mouser (a major electronic component distributor in the USA) was selling a $2.95 USD duplex wall receptacle for about $130 USD (after all, it had gold plated contacts)!
The audiophile crowd cries that the additional 0.02% - 0.04% purity of Oxygen-Free Copper (OFC) makes a magical, unbelievable difference in the sound of their 33-1/3 RPM vinyl records. But, that's a debate for another forum. Please don't take this as a challenge to start one.
Read a good explanation on the subject at https://www.copper.org/resources/properties/microstructure/coppers.html
Cheers,
DaveM

It has to be quite pure, because alloys with >98% copper (phosphor bronze for instance) have double the resistivity of copper.

 

Not true. Almost all commercially available copper wire is 99.95% or higher pure copper, the rest being cuprous oxide and other metallic imputities.

It has to be quite pure, because alloys with >98% copper (phosphor bronze for instance) have double the resistivity of copper.

OK, I stand corrected IEC/BS EN 60228 says max resistance per km of 4mm2 (1/2.26) should be 4.61Ω giving a ρ = 1.89e-8Ωm which I'd assumed was down to impurities, but of course it allows also for a tolerance on x-sectional area/diameter... which I guess is a larger factor?

 

OK, I stand corrected IEC/BS EN 60228 says max resistance per km of 4mm2 (1/2.26) should be 4.61Ω giving a ρ = 1.89e-8Ωm which I'd assumed was down to impurities, but of course it allows also for a tolerance on x-sectional area/diameter... which I guess is a larger factor?

Having tested many reels of cable with ohmmeter and micrometer, I conclude that manufacturing tolerances have improved markedly since the standards were introduced. Most of them were under size, but not by so much that they were above the resistance specification.

 

Having tested many reels of cable with ohmmeter and micrometer, I conclude that manufacturing tolerances have improved markedly since the standards were introduced. Most of them were under size, but not by so much that they were above the resistance specification.

Well better tolerance = reduced material cost = more profit

 

Well better tolerance = reduced material cost = more profit

Found many reels of copper-coated-steel passed off as copper! (even more profit)

 

I have come across a fair amount of that coper colored steel wire, mostly used for COMM links, where a bit of extra resistance is not a big deal. BUT the stuff is mizerable to work with because it is quite stiff steel, difficult to bend for terminals and inside wiring. BUT it does not seem to stretch and sag. So THERE IS A PLACE FOR IT, just not everywhere.