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How to Intall a Fuse Tap

Author: Apogeeweb
Date: 30 Mar 2022



Ⅰ Fuse Types and Form-factors

Ⅱ Installing a Fuse Tap

Ⅲ How to Install a Fuse Tap in Details

Ⅳ Tips of Fuse Tap to Avoid Some Serious Consequences.

Ⅴ Buying the Fuse Tap

Ⅵ Frequently Asked Questions about the Fuse Tap

1. What's a Fuse Tap do?

2. Which Fuse Slot Should I Use for My Fuse Tap?

3. Which Side of a Fuse is Positive?

4. Can you stack fuse taps?

5. Can you Double Fuse Tap?


A "fuse tap" is an electrical component that acts as a power splitter and is intended to be inserted in the fuse box of a vehicle. The end of the tap resembles a fuse. Instead of the original fuse, this end is inserted in the fuse slot. The tap contains a "box" with a slot where the original fuse should be placed to provide the original functionality. That box also contains a second fuse slot for the "split" which exits the box through a pigtail/cable.

The advantage of using a fuse tap overcutting and reconnecting wires is that the alteration may be undone and the original configuration restored. Another advantage is that the fuses in the fuse box are recorded and labeled, making it easier to find the correct connections.

Fuse taps can also be used for other purposes, such as installing a new socket or connecting a new power line to a power source.

You will learn from the video: How To Install A Fuse Tap & How It Works - Hardwire

 Fuse Types and Form-factors

What is the Fuse Tap?

Fuse taps are ingenious metal and plastic inserts that may split a single fuse location on your fuse box into two distinct fuse positions. They are an excellent generic approach to power an additional circuit separately.

There are several types of automobile fuses, but three are particularly popular.

1.Regular / Medium

2.Mini / Small

3.Miniature / Low-profile


Please keep in mind that names can be contradicting and/or confusing, thus it is best to measure the fuse as well as physically verify the fuse form factor.

Medium Medium
Mini Mini
Micro Micro

Fuse taps come in matching sizes.

 Installing a Fuse Tap

We'll now connect our two fuse taps so that the load side of the power socket is wired to the battery side of the tapped slot rather than the battery side of the power socket slot. We'll refer to the slot we're about to tap as "1," and the power socket slot as "2."

Here's a diagram of the fuse tap. The letters A-E will be used to denote the various points.

Following are some examples based on this naming convention:

  • The "common" side of the tapped slot tap is A1 or C1.
  • The original fuse in the power socket slot is CD2.
  • The "original" side of the power socket slot tap is D2.

Connect the E1 and E2 pigtails to one another. The connection must be disconnected.

Then, depending on whether the tapped slot was previously empty or occupied, go to the appropriate section.

The following is a step-by-step instruction to installing a fuse tap. Please take caution, as with any electrical installation, to reduce the danger of personal harm and equipment damage.

  1. Remove the battery cables or use a disconnect switch to disconnect the vehicle's battery power.
  2. Remove the fuse from its circuit slot. (Learn how to choose the appropriate circuit for your fuse tap in the section below.)
  3. Insert the wire from the new electrical device into the fuse tap's connector. As with any other electrical connection, make sure you cut, strip, and crimp the wire as needed.
  4. Connect the fuse tap to the fuse block's open circuit.
  5. Insert the fuse from the fuse block into one of the fuse tap's circuits, followed by a new fuse for the newly added electrical component.
  6. Reconnect the battery electricity to the car.

 How to Install a Fuse Tap in Details

The first step is to locate an appropriate circuit to tap into and ensure that you have the proper type of fuse. Then install it, test it, and connect it. Let's get started.

Find the best fuse to tap

Step 1

Find an internal fuse box that is easily accessible and offers a straight and short path for the power cable to be run to the accessory. The fuse tap will not provide the water- or heat-proof connection required for under-the-hood electrical wiring if a fuse box is used in the engine compartment.

Step 2

Remove the fuse box's cover. The fuses will be depicted on a diagram or chart, with their locations and functions labeled. Determine an appropriate fuse and circuit to tap into that will power the automobile on and off.

  • Good options include a radio, an inside light, a lighter-type charger connector, and so on.
  • Avoid employing circuits for the starter, airbags, sensors, and unidentified "alphabet soup" labels, among other things.
  • If it powers on and off with the car, you can use an empty fuse socket. If feasible, use a meter to test.

Install Bay ATC Fuses


Step 3

 Determine the type of fuse so that you can purchase the correct size fuse tap and accessory fuse. The type of fuse used in your car should be identified in the owner's manual.

  • Types: ATC, Low-Profile Mini, Micro2, ATM (MiniATC)
  • A 1A or 3A accessory fuse will suffice for the majority of applications. Never utilize an accessory fuse with a rating greater than 5A.

How to install the fuse tap

Step 4

Turn off the vehicle. Remove the OEM fuse and set it away.

Step 5

[If you don't have a meter, skip this step.] Start the automobile. Test and identify the hot (+12V) and load (0V with fuse pulled) sides of the fuse socket with a DC voltmeter, and ensure that the hot voltage changes on and off with the car.

Step 6

Connect (crimp) the fuse tap wire to the power wire of your new accessory device.

Step 7

With the engine off, insert the fuse tap into the socket of the removed fuse, with the common side contact to the hot socket and the wire side contact to the load socket.

Step 8

Insert the proper fuse for the new device into the accessory fuse slot on the tap.

  • The accessory fuse will be wired in parallel with the factory fuse, resulting in the factory circuit being fused at the total of their ratings, which could be hazardous to the wiring if the aftermarket fuse is too large.
  • Use an additional fuse that is rated significantly lower than the factory fuse for safety.
  • Use an accessory fuse with a current rating of 5A or less.

Test, troubleshoot, then button it up


Step 9

Turn on the car and the new device.

  • If the accessory does not have power or cannot be turned on, turn the car off, reverse the fuse tap in its socket, and then turn the car back on.
  • Okay, if the attachment is powered on:

Step 10

Turn off the vehicle and replace the factory fuse in the appropriate slot of the fuse tap, if it was removed in Step 4. (Adding a fuse to a circuit that did not previously have one may cause harm to the factory wiring.)

Step 11

Put the new power wire in place. Put the fuse box cover back on. You may need to adjust the cover to allow the fuse tap and new wire to sit nicely inside without being pinched or tampered with.

Blindly throwing in fuses and plugging it into your fusebox could end in some serious consequences.

Ⅳ Tips of Fuse Tap to Avoid Some Serious Consequences.


The fuse you remove must be inserted into the slot closest to the metal prongs. This section of the circuit replaces the fuse's original position.

If you place the fuses incorrectly, the fuses may blow or the electrics may be damaged.

This is because the components will be protected by fuses that are not properly rated.


Because a fuse is only a link in the circuit, it can be inserted either way. However, because you are taking a live feed from the fuse box to utilize elsewhere, you must install the fuse tap correctly.

Examine the image once more. You can see that power is applied to the left terminal, which connects to both fuses. If you plug it in backward, power enters from the right terminal, travels through one fuse, and then through a second fuse before reaching the additional device.

Running two fuses in parallel is a terrible idea. It will put a strain on the original fuse, which may cause it to continue blowing (cutting power to the new circuit), but it may also make the second fuse blow slower.

This may not blow at the appropriate amperage or a quick enough rate to protect whatever is connected to that circuit.

You'll have to use a multimeter to figure it out. 1 probe on a car earthing point, a multimeter reading DC volts, and touching each terminal One terminal will indicate around 12 volts, while the other will display no reading.


The power rating of whatever you're powering is usually listed on the box or in the handbook. This automobile camera, for example, consumes 1 Amp. Your fuse should ideally be as close to the amperage rating as feasible without going below it. However, certain electrics can rise above that on startup, so start as near to that as possible.

If the fuse blows instantly or regularly, double-check the wiring and raise the fuse size significantly.


Will the fuse box be able to handle it? The fuse box is intended for your vehicle (obviously). However, the circuit that powers the fuse you removed may only be adequate for the estimated amperage. Using extra power through the same circuit may cause the relay, connections, or PCB tracks to overheat. If you kill any of them, you'll be getting a new SAM unit (fuse box).

Fuses are either flipped to live or permanently live. So, you'll need to decide how you'll power whatever you're installing. For example, if you're powering a dash camera, you don't want it to run while the motor is turned off. In that situation, you'd want a switched live connection so the camera shuts off when you turn the key.

When powering anything like a tracker, you want it to be on all of the time. So decide on a permanent residence.

You can figure it out by looking at the fuse list and determining whether everything connected to a certain fuse is switched or live. However, using a multimeter in voltage checker mode is a better option. Remove a fuse and probe both connections after connecting the black lead to the battery's negative post. It's switched live if you don't receive any readings on either.

Turn on the ignition and test again; you should get a reading on one of the connections. Keep that relationship in mind. If you always receive a reading on one connection, you have a permanent fuse connection.


The next step is to determine which of the circuits you should tap into. Each circuit within the SAM is only rated for a maximum amperage of a specified value. The width of the PCB tracks, the ratings of the transistors, relays, and other components, and so on.

If you're powering something with a high amperage rating, avoid circuits that use a low-powered fuse. Ideally, choose a circuit that has a high fuse rating and can power a large number of objects. These circuits are designed to withstand a greater amperage peak and are unlikely to overrun.

 Buying the Fuse Tap

You will require two taps. One for the fuse to be tapped and one for the fuse to be tapped. In the preceding step, you should have recognized those fuses and their form factors.

In the internet store, look for "fuse tap." Consider including a size modifier, such as "mini" or "micro," but perform a visual scan/comparison of the photographs in the listing regardless of the title.

Prefer an item with a crimpable connector that you can attach to the wire that will be plugged into the tap's pigtail. A pigtail with a (usually) blue tube that is supposed to be crimped with force is a less favored choice. A connector is easier to attach and can be removed in the future if necessary.

You'll also need an extra fuse with a rating equal to or greater than the "specified fuse rating." The extra fuse should have the same form factor as the tapped fuse slot. In some fuse tap listings, a fuse is included in the package. Though automobile fuses are inexpensive, it would be good to have one extra fuse with the purchase.

 Frequently Asked Questions about the Fuse Tap

1. What's a Fuse Tap do?

A fuse tap allows you to obtain 12 volts from your vehicle's fuse box for a low-power device such as an active signal processor, amplifier turn-on circuit, radar detector, or backup camera. Because of the thinness of the power wire on a fuse tap, you should only use one to power a device that draws no more than 5 amps of current or outputs no more than 52 total watts.

You should never use a fuse tap to power an amplifier since it is detrimental to your vehicle's electrical circuitry. A strong power connection must be run directly from the amplifier to the battery when using an amplifier.

2. Which Fuse Slot Should I Use for My Fuse Tap?

When selecting the circuit in your vehicle fuse block to use for fuse tap installation, there are numerous key considerations to consider.

  • If feasible, use an already empty circuit slot.
  • If none of the aforementioned options are available, choose a fuse that powers a utility function (such as the rear window wiper, music system, and so on) rather than one that powers a crucial function (such as the ABS, headlights, etc.)
  • Because the pigtail will most likely need to be tucked in beneath the fuse block cover, choose a fuse that is suitably situated to allow for safe wire connection and installation.

3. Which Side of a Fuse is Positive?

If you put a multimeter across it, the end that is receiving power will be positive, while the other end will be chilly. If you turn it around, the hot end will be in the same spot.

4. Can you stack fuse taps?

Stackable to enable several fuse taps in one spot. Because of its unique form, it may be attached directly to the battery's side terminals. Taps are designed to clip onto existing fuses and provide an additional connecting point for slip-on terminals.

5. Can you Double Fuse Tap?

To utilize a dual fuse holder, first, connect the wiring from the new electrical component to the wire stem on the fuse tap, and then seal the wires together using a crimper. Then, simply remove an existing fuse and insert the fuse holder into the now-available socket.




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