Wire - Revision history

Satiric: Add EN 3197, EN 2853

2024-12-16T19:32:26Z

Add EN 3197, EN 2853

Satiric: summarize wire capacitance

2023-07-24T04:38:22Z

summarize wire capacitance

Satiric: summarize wire impedance

2023-07-24T04:32:09Z

summarize wire impedance

Satiric: /* IEC 60287 */

2023-07-24T04:21:50Z

IEC 60287

Satiric: Formatting

2023-06-09T01:53:19Z

Formatting

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Satiric: Formatting

2023-06-09T01:51:01Z

Formatting

Satiric: Replace table image with a native table

2023-06-09T01:49:46Z

Replace table image with a native table

Show changes

Satiric: mention process for sizing wires

2023-06-09T00:58:02Z

mention process for sizing wires

Satiric: emphasize that NASA's standards might be conservative

2023-06-09T00:53:01Z

emphasize that NASA's standards might be conservative

Satiric: Added summary of NEC wire sizing standards

2023-06-01T05:00:50Z

Added summary of NEC wire sizing standards

@@ Line 208: / Line 208: @@
 ===SAE AS50881===
 [https://www.sae.org/standards/content/as50881/ SAE AS50881] is the current SAE standard for wiring in aerospace vehicles. The method described in this standard compensates for the number of wires in a wire bundle, what size they are, and how many are carrying current. The older version of this standard is MIL-W-5088.
 ===MIL-STD-975===

← Older revision		Revision as of 04:38, 24 July 2023
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	===Capacitance===		===Capacitance===
		+	Wires do have a small amount of capacitance, i.e. their resistance decreases slightly as you increase frequency (until the inductance takes over, and the resistance starts increasing again). Its effect is almost always extremely minimal and can generally be ignored.

	==Standards==		==Standards==

← Older revision		Revision as of 04:32, 24 July 2023
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	===Impedance===		===Impedance===
		+	The impedance of a wire is its resistance at a given frequency. Generally speaking, its impedance will be low at low frequencies and higher at higher frequencies.
		+
		+	Usually, you only have to think about this when dealing with high frequency signals. CAN bus, for instance, specifies an impedance of 120 ohms at whatever frequency your bus is operating at. So in theory for CAN bus you should be looking for cable that has an impedance of 120 ohms (in practice, often this doesn't matter and you can just use any old shielded twisted pair 22 gauge or whatever. The designers of CAN chose 120 ohms in part because twisted pair cable often has an impedance around 120 ohms).
		+
		+	One other place you may see an impedance specification for wiring is for coax cables, which often specify an impedance of 50 ohms.
		+
	===Capacitance===		===Capacitance===

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 ===IEC 60287===
-Under this standard, you calculate the wire size based on thermal characteristics of the wire. For Formula SAE use, probably the most useful equations are those marked "in free air", as there are many equations that are for use in underground applications. With the methods described in this standard, you can also calculate the ampacity of multi–wire cables, or even shielded cables, based on the exact materials the cable is made out of.
+Under this standard, you calculate the wire size based on thermal characteristics of the wire. For Formula SAE use, probably the most useful equations are those marked "in free air", as there are many equations that are for use in underground applications. With the methods described in this standard, you can also calculate the ampacity of multi–wire cables, or even shielded cables, based on the exact materials the cable is made out of. This method can be helpful for high-power cables, like those used in the tractive system of an EV car.
 ===National Electrical Code===

@@ Line 5: / Line 5: @@
 American Wire Gauge is the standard system for wire sizing in North America. Wire sizes are logarithmically stepped, with a larger gauge signifying a smaller cross section. The formula for calculating diameter of a wire for standard and metric units is as follows, where <math>d_n</math> is the wire diameter and <math>n</math> is the wire gauge. Note that this is the diameter of a bare solid-core wire—stranded wire will have the same cross-sectional area, but a larger overall diameter.
 {| class="wikitable" style="height: 505px; width: 797.183px;" data-mce-style="height: 505px; width: 797.183px;"
 |- style="height: 18px;" data-mce-style="height: 18px;"
 | style="height: 18px; width: 102px;" data-mce-style="height: 18px; width: 102px;"|'''AWG'''<br />
-| style="height: 18px; width: 193px;" data-mce-style="height: 18px; width: 193px;"|'''Solid-core diameter (in/mm)'''<br />
+| style="height: 18px; width: 193px;" data-mce-style="height: 18px; width: 193px;"|'''Solid-core diameter (in)'''<br />
-| style="height: 18px; width: 157px;" data-mce-style="height: 18px; width: 157px;"|'''<strong>Solid-core diameter (mm)'''</strong>
+| style="height: 18px; width: 157px;" data-mce-style="height: 18px; width: 157px;"|'''Solid-core diameter (mm)'''
 | style="height: 18px; width: 133px;" data-mce-style="height: 18px; width: 133px;"|'''Area (mm²)'''<br />
 | style="height: 18px; width: 153px;" data-mce-style="height: 18px; width: 153px;"|'''Resistance, copper (mΩ/m)'''<br />
@@ Line 157: / Line 156: @@
 | style="height: 4.21668px; width: 210.183px;" data-mce-style="height: 4.21668px; width: 210.183px;"|103.2
 |}
 ===Metric===

@@ Line 16: / Line 16: @@
 ===Ampacity===
 Theoretically, any wire can carry any amount of current, as long as the voltage drop across the wire does not drop the voltage to an unusable level. However if the wire is too small it could heat up to an insane temperature and burn your car to a crisp. Ampacity is the maximum current you can safely pass through the wire. A larger gauge wire will be able to carry more current, but will be heavier.
 ===Voltage Drop===

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 ===MIL-STD-975===
-This is NASA's standard for the selection of standard electronic parts. In Appendix A, Section 3.16, they give a method of finding a wire's ampacity, calibrating for wire temperature rating and the number of wires in a wire bundle. Because it's NASA's wiring standard, it assumes a vacuum, with no heat dissipation due to conduction or convection.<ref>"What's Outer Space like?" JAXA. https://iss.jaxa.jp/kids/en/space/401.html. Accessed 24-Mar-2023.</ref>
+This is NASA's standard for the selection of standard electronic parts. In Appendix A, Section 3.16, they give a method of finding a wire's ampacity, calibrating for wire temperature rating and the number of wires in a wire bundle. Because it's NASA's wiring standard, it assumes a vacuum, with no heat dissipation due to conduction or convection, so it might be conservative for FSAE use.<ref>"What's Outer Space like?" JAXA. https://iss.jaxa.jp/kids/en/space/401.html. Accessed 24-Mar-2023.</ref>
 ===IEC 60287===

@@ Line 58: / Line 58: @@
 ===IEC 60287===
 Under this standard, you calculate the wire size based on thermal characteristics of the wire. For Formula SAE use, probably the most useful equations are those marked "in free air", as there are many equations that are for use in underground applications. With the methods described in this standard, you can also calculate the ampacity of multi–wire cables, or even shielded cables, based on the exact materials the cable is made out of.
 ==References==
 [[Category:Electronics]]