wire guage simple question

[EE_Bota]

Now sure if it helps, but I have 2 x(750MCM 3 phase) for a total of 6 750MCM
conductors running a production process. These are parallel. So, apparently you can do what it makes sense. I didn't know what to do otherwise, and neither did the PE I hired to help sort the zig-zag transformer grounding.

These conductors are made to be the exact same length.

I will tell you what does NOT work in parallel: DC motor interpoles. Most interpoles I have ever seen are series connected, but some of the low diameter European motors have the interpoles connected in parallel! What a hateful thing to do.

 

[hr3]

Why would one assume he is talking about 12 volts dc ??? Voltage drop in % is the same but if you lose 2 volts from a 120v supply not much of a problem.. When you lose 2 volts from a 12v circuit,,Well that's a different story,,,

Like he said he had a simple question.. kis

 

[rd_macgregor]

ModMech,
One small glitch in your calculations. Circumference is 2piR, while area is pi R squared; you mixed the two and showed a formula for calculating twice the area.
BOB

 

[killdozerd11]

As i have worked as a maintenance mechanic in a bolt factory

The general rule is... Bubble gum-Baling wire and tape and whatever you have on hand to get it safely back on line

And do the correct repair after the work day is done

If you ever do this for a living you got to love over time and working under pressure and you have to think on your feet

I would not do what you asking about as a permanent fix

 

[bdeboer]

Now sure if it helps, but I have 2 x(750MCM 3 phase) for a total of 6 750MCM
conductors running a production process. These are parallel. So, apparently you can do what it makes sense. I didn't know what to do otherwise, and neither did the PE I hired to help sort the zig-zag transformer grounding.

This is allowed by the NEC for larger conductor sizes/amperages. Due to the fact the wire & conduit sizing would not be practical.

 

[ModMech]

10ga carries a lot more than 15 amps... and 16ga will carry more than 3.7.

If you look at the chart it specifically gives the rating I offered for automotive load carrying.

AC vs DC does matter to some degree (but, not really).

No, it matters, really. Most automotive wire, assumed in this conversation, has a completely different inductance and frequency response from stranded wire of the same area. For normal power and ground circuits however, you are correct it really doesn't matter if referring to AC or DC loads.

Most electricians you talk to will tell you 14ga will carry 15A, 12ga carries 20A, 10ga 30A. This is all in the context of romex carrying AC and fairly short runs (aka, not 300 feet).

My father-in-law is a Master Electrician with 30+ years as a Journeyman and he will tell you that the load carried is dependant on the circuit voltage, power factor and length of the run.

 

[DonnieP]

From Canadian Electrical Code:
12-108 Conductors in parallel (see Appendix B)
(1) Conductors of similar conductivity in sizes No. 1/0 AWG copper or aluminum and larger shall be permitted
in parallel provided that they are
(a) free of splices throughout the total length;
(b) the same circular mil area;
(c) the same type of insulation;
(d) the same length; and
(e) terminated in the same manner.
(2) The orientation of single-conductor cables in parallel, with respect to each other and to those in other
phases, shall be such as to minimize the difference in inductive reactance and the unequal division of
current.
(3) Conductors of similar conductivity in sizes smaller than No. 1/0 AWG copper shall be permitted in parallel
to supply control power to indicating instruments and devices, contactors, relays, solenoids, and similar
control devices provided that
(a) they are contained within one cable;
(b) the ampacity of each individual conductor is sufficient to carry the entire load current shared by the
parallel conductors; and
(c) the overcurrent protection is such that the ampacity of each individual conductor will not be
exceeded if one or more of the parallel conductors becomes inadvertently disconnected.
(4) Where the size of neutral conductors is reduced in conformance with Rule 4-022, neutral conductors
smaller than No. 1/0 AWG shall be permitted in circuits run in parallel, provided that they are installed in
conformance with the requirements of Subrule (1)(a), (b), (c), (d), and (e).

 

[dcyrilc]

I was wondering if this would hold true.
If I wanted to have a 10 gauge wire but run two 14 gauge ones on the same terminal. would this amount to a 7 gauge?Ive seen people double up conductors before to gain the lower gauge.
Thanks

The short answer is NO. The math doesn't work that way. Two number 14's would be closer to a number 10.

In certain cases, wire can be doubled and run parallel for higher amperages, but it doesn't work the way you were asking.

 

[Soundguy]

Only reason I recommend separate fusing, is what if one of the two conductors takes some damage? You can dump *all* of the current to a single conductor but still be within the operating range of the fuse.

-rus-

if the wire takes damage like chafing... hopefully the fuse will pop!

soundguy

 

[patrick_g]

Is there a magic conveyor belt involved in this somewhere?