:: the problem with MADE in CHINA cables is ...

i bet many hobbyist have come across the question of, HOW GENUINE are these copper cables made in CHINA?

you don't know until you buy some and then measure the overall resistances and calculate vs the cross section area.

below are some data from websites

	item	平方 (mm2)	CNY	$$$/mm2	Ω/1000m	stranding	AWG	Wt(Kg) / 1000m	nΩ.m	Mils^2	Ondk 1s (amps)	Ondk 999s (amps)	30C rise to 60C (amps)	*LQ = low quality
hobby RC shop	532620918891	25.14	$50.00	1.989	1.25	5000/.08	4		31.43	38967	3915.8	123.9	145.3	LQ
hobby RC shop	45367363912	0.75	$1.50	2.000	39.50	150/.08	18		29.63	1163	124.0	3.9	13.7	LQ
hobby RC shop	532620918891	12.07	$18.00	1.491	2.60	2400/.08	7		31.38	18709	1883.1	59.6	87.7	LQ
hobby RC shop	532620918891	16.09	$25.00	1.554	1.90	3200/.08	6		30.57	24940	2576.7	81.5	109.8	LQ
Braiding	43964956175	8.45	$4.80	0.568	2.28	480/.075		85	19.30	13098	2143.5	67.8	111.5
Braiding	39055875646	4.24	$2.40	0.566	4.55	240/.075		43	19.30	6572	1075.5	34.0	69.3
Braiding	22552776369	25.45	$15.00	0.589	0.76	1440/.075		254	19.30	39448	6455.6	204.2	238.7
	calmont	24.90			0.73	19/(16)	3	227	18.18	38595	6705.1	212.1	249.6	sample
	calmont	2.38			9.01	1176/(44)	14	23.8	21.44	3689	543.4	17.2	41.9	sample
	calmont	14.70			1.39	1813/(38)	6	147	20.43	22785	3522.5	111.4	154.4	sample
	calmont	5.37			3.61	133/.09	10	125	19.39	8324	1355.9	42.9	81.2	sample
	calmont	0.33			61.40	66/40	22	3.1	20.26	512	79.8	2.5	11.3	sample
	calmont	8.37			2.10	1	8	74.4	17.58	12974	2330.9	73.7	121.6	sample
	calmont	13.30			1.32	1	6	118	17.56	20615	3707.9	117.3	167.6	sample
welding lead	16756217099	16.00	$9.00	0.563	1.24		5		19.84	24800	3948.0	124.9	168.5
welding lead	16756217099	10.00	$7.00	0.700	1.98		7		19.80	15500	2472.5	78.2	122.1
welding lead	16756217099	25.00	$13.00	0.520	0.79		3		19.75	38750	6196.9	196.1	230.4
	LIBAN	6.00			3.08	1		53	18.48	9300	1589.5	50.3	92.0	sample
Earthing Cu	44392603636	25.00	$16.50	0.660	0.91		3		22.75	38750	5379.7	170.2	200.0
AGR silicone	545870228257	6.00	$3.10	0.517	3.39	84/0.3	10		20.34	9300	1444.1	45.7	83.6
AGR silicone	545870228257	4.00	$2.22	0.555	5.09	56/0.3			20.36	6200	961.8	30.4	63.1
PTFE	528684442893	1.00	$0.88	0.880	19.00	19/0.26			19.00	1550	257.7	8.2	26.0
RV PVC	534957029863	1.00	$0.63	0.630		1				1550
AGR silicone	22501955879	0.75	$0.50	0.667	26.70	42/.15			20.03	1163	183.4	5.8	20.2
PTFE	546896145948	0.35	$0.70	2.000	49.50	19/.16	22		17.33	543	99.0	3.1	13.8
	Wiki AWG 8	8.37			2.06		8		17.24	12974	2376.9	75.2	124.0	sample
	Wiki AWG 6	13.30			1.30		6		17.29	20615	3765.8	119.1	170.2	sample
	Wiki AWG 4	21.20			0.82		4		17.38	32860	5971.5	188.9	233.6	sample
	Wiki AWG 1	42.40			0.41		1		17.38	65720	11943.0	377.9	376.9	sample
	annealed								17.2					COPPER
	not annealed								16.8					COPPER
AMASS	36457901332	16.09	$29.00	1.802	1.21	3200/.08	6		19.47	24940	4045.7	128.0	172.4	original?
AMASS	36457901332	8.29	$14.00	1.689	4.10	1650/.08	8		33.99	12850	1194.0	37.8	62.5	LQ
WIPOUS	534955000055	8.51	$7.14	0.839	2.16	168/.254	8		18.38	13191	2266.7	71.7	117.7
WIPOUS	534955000055	21.08	$12.00	0.569	0.88	196/.37	4		18.55	32674	5563.2	176.0	218.0
WIPOUS	534955000055	5.32	$4.13	0.776	3.41	101/.254	10		18.14	8246	1435.7	45.4	86.2

you can try to measure the circumference of the conductor by wrapping it with many turns of a thin wire like AWG40-44, then unwrap it and find out the diameter, then find out the approximate area.

the fixed constants we know in life are the resistivity of COPPER (about 17.2nΩ.m annealed). by measuring the resistance of a known length (with the known cross section area), we can find the resistivity. you will of course need a super sensitive low resistance ohm meter (assuming this will not be a problem)

column description
1 = cable general category
2 = cable ID if any
3 = conductor area
4 = CNY price if any
5 = cable general category
6 = unit price per area
7 = stated resistance per km
8 = conductor stranding
9 = equiv AWG no.
10 = stated wt per km
11 = stated/calculated resistivity
12 = equiv area in mils
13 = ONDERDONK current capacity
14 = ONDERDONK current capacity
15 = Temp rise approx current capacity (approx PREECE)
16 = remarks

but without doing so, we can see already from the data provided by vendors, there are already things not quite right with the quality of the conductors. the many sample/types shown (number tags are TAOBAO item IDs) allows us to see that if a finely stranded cable have a worse case resistivity of about 21nΩ.m, why are those MADE in CHINA conductors going off into 30nΩ.m?

this would mean when high current circuits are deployed, you need to buy about 33% more cables (and more weight) to secure a certain current carrying capacity.

by relying  on the fact that 99.99% of buyers do not own a low-ohms meter to cross check the quality of the cables, sellers can promote "miraculous geniune copper cables" when in fact they could be copper cladded steel.

have you measured some lately?