Why Do 7-Way 12 Volt Circuits have 12 Gauge Wire While When 10 Is Recommended

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Question:

I have a clarifying question about the wire size for the trailer battery charge wire. From the product description: Black, Battery,12 Gauge. Advice from another etrailer post: The wire that runs from the vehicles battery to the 7-way trailer connector and then from the 7-way trailer connector to the trailer battery should be at least a 10 gauge. If you dont have any 10 gauge wire you can purchase part # 10-1-1 by the foot. Please note, you will need a circuit breaker part # 9510 on this charge line wire about 6inch away from the battery on the tow vehicle. The 7-way trailer connector can then be used to attach and disconnect the charge line between the tow vehicle and trailer. helpful expert reply by: Conner L This kit comes with 10 ga wire for the battery charge wire, and the part number listed in the expert response is for a 40 amp circuit breaker, but then all of the 7-pole sockets listed on your site choke down to 12 ga. at the plug harness. Why? 12 gauge wire is not rated for 40 amps. Will the 12 ga in the charge line create an issue? Can you help me wrap my head around what Im seeing as conflicting information?

asked by: Sean K

0

Expert Reply:

This is a really great question but 12 gauge wire ran in a very short length doesn't have nearly as much resistance as it does in longer lengths so while the 7-ways will have short runs of 12 gauge wire for the 12 volt accessory circuit you still would want to run the longer lengths of wire for this circuit in 10 gauge like part # 10-1-1. This is because the longer the wire the more the resistance increases.

expert reply by: Jameson C

0

Answer 1

Since the Hopkins 7 and 4-Way trailer connector #HM40975-11998 includes a hardwire harness it technically could be installed on any vehicle, including your 2002 Toyota Tundra with a 4-Way connector. But you will need to do some hardwiring and extra…

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Answer 2

We have all of the wiring you need for your 1996 Ram, but there is no all-in-one harness available. First I recommend part #HM40975-11998. This is a 7-pole and 4-pole trailer connector with the bracket and wiring. This will hardwire to the existing…

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Answer 3

We can get you everything you need for towing with your 2017 Toyota Sienna XLE. By plastic shield, I believe you are referring to the appearance panel underneath the Sienna, and that will have to trimmed a bit in each of the hitches available for the…

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Answer 4

The Blue and Orange (or Red) wires are meant to carry the 12-v accessory power and the brake control output to the 7-way installed at the rear. The wires terminate in the engine compartment under the master cylinder. The red wire would be lengthened…

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Answer 5

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

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Answer 6

If you just need a 4-pin to 7-pin trailer wiring adapter, then you can use part #C57672. This will plug into the 4-pin trailer connector on your brother's vehicle and give him the 7-pin socket for the trailer. Keep in mind, this will only give…

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Answer 7

Hey Dave, congrats on the new truck! Since you have the B&W Companion item #BWRVK3500 or the sliding Companion item #BWRVK3400-5W, you'll need the B&W Turnoverball Underbed Gooseneck Trailer Hitch w/ Custom Installation Kit item…

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Answer 8

Hey Mark, thanks for the pictures. The Curt Dual Connection Socket w/ Bracket item #C36GJ isn't going to fit without some modifications. It will plug directly into your Silverado's OEM USCAR wiring system but you'll have to cut about an…

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Answer 9

The difference between the Class II and Class III hitches has to do with their Gross Trailer Weight (GTW), their Tongue Weight (TW), and their Hitch Receiver Size. Class II trailer hitch receivers have a 1-1/4 inch receiver and can be rated up to…

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Answer 10

Hey Debra, thanks for reaching out! To install wiring on your 2021 Colorado you'll need the 7-Pole and 4-Pole Trailer Connector Sockets w/ Mounting Bracket and Wiring #HM40975-11998. Since your truck didn't come with a factory connector on…

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Answer 11

Hey Gregory, thanks for reaching out! I really like the etrailer Trailer Hitch Receiver #e55ZR as well - I know you'll be happy with it! When it comes to wiring, a 4-Way is used for basic trailer lighting, but since you'll be towing a trailer…

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Answer 12

You assumed correctly. The Blue and Yellow pigtail leads on the Curt Adapter Item #C57672 do not have to be connected to use the Curt Echo item #C51180. You will just need to connect the 4-way to the adapter and then run the ground and power wires.

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Why Do 7-Way 12 Volt Circuits have 12 Gauge Wire While When 10 Is Recommended

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