6/3 or 6/4 Wire for Hot Tub – Which One Is Suitable?
The hot tub is a great way to refresh yourself after a tiring day. The best results from a hot tub rely on the wire gauge. Generally, the hot tub uses 6 AWG wires, and this wire type has 2 and 3 numbers of actual wires. So, one obvious question arises: 6/3 or 6/4 wire for hot tub?
The answer depends on a few factors, such as the hot tub’s specific amperage and voltage rating. The 6/3 wire is suitable for hot tubs since it perfectly works between 40 – 75 amps and 220/240 V. But there is more to get the right gist.
I discussed in-depth in this comprehensive guide which wire to use between 6/3 and 6/4 for your hot tubs.
What Is 6/3 Wire?
The 6/3 wire consists of 3 conductors with a bare ground cable. Soft-stranded bare annealed copper is used to manufacture the conductors.
This wire type carries 55 – 60 amps of electricity. But the carrying amps depend on the temperature. Find the below chart for a better understanding,
| Temperature Rating | Carrying Amps |
| 60 degrees | 40 amps |
| 75 degrees | 60 amps |
| 90 degrees | 75 amps |
Such a higher temperature rating means that it can carry more electricity. For this reason, the 6/3 wire can be used for,
- Hot tub
- Sub panel
- Stove
- Tesla charger
- Electrical range
However, don’t assume you can use 6/3 wires for every situation. The prime condition is if the appliance rating falls between 55 – 75 amps; 6/3 wire is the best solution.
What Is 6/4 Wire?
The 6/3 wire consists of 4 conductors with one ground cable. This wire comes with a voltage rating of 600V. Also, it works perfectly between -40°C to +90°C temperature.
The conductors are made of copper, letting the wire carry 44 amps to 60 amps quite easily under different temperature ranges.
| Temperature Rating | Carrying Amps |
| 60 degrees | 44 amps |
| 75 degrees | 55 amps |
| 90 degrees | 60 amps |
You can use 6/4 wire for the below purposes,
- Home appliances
- Temporary power
- Lighting
- Tools
Whatever home appliances have 44 – 60 amps of range, use the 6/4 gauge wire.
6/3 or 6/4 Wire for Hot Tub- Which One to Choose?
There are a few factors that you need to consider whether to use 6/3 or 6/4 wires for your hot tubs. Before deciding on the wires, it is important to know the hot tub’s amperage and voltage rating.
As you can see, a hot tub’s standard amperage and voltage ratings are 40 – 75 amps and 220/240 V, respectively. You should use 6/3 wires for hot tubs when the hot tub’s amps rating is between 30 – 60 amps, and the voltage rating is 220/240 volts.
On the other hand, using 6/4 wires couldn’t be better.
However, these wires are suitable for 30 – 60 amps but have a voltage rating of 600 volts. But many hot tubs come with 220/240 voltage ratings. So, if you use them in your hot tub, the appliance may damage.
According to a member of Poolspa Forum, 6/3 is fine and yes you want the ground insulated…. it’s just safer. You can easily get by with 8 awg with a short run like that. 8 THHN is rated at 55 amps (NEC book).
Frequently Asked Questions (FAQs)
What Gauge Wire to Use for a Hot Tub?
What gauge wire to use is one of the crucial factors when wiring a hot tub. This will let you determine the flow of current through the wire.
Follow a simple rule while choosing the wire gauge. Select one size bigger wire gauge than the circuit breaker used for the hot tub.
For example, if the hot tub circuit breaker is 20-amp, choose an 8-gauge wire.
Moreover, if the hot tub circuit breaker is 30-amp, choose a 6-gauge wire.
Another vital consideration is the length of the wire. The longer wire needs higher gauge cables. The reason is longer wire offers more resistance.
Last, the wire should also be adequately insulated. Hot tub generates excessive heat. It can cause a fire if the wire is incorrectly insulated. So, proper insulation is a must.
What Size Wire Do I Need for a 220V Hot Tub?
What Gauge Wire to Use for a Hot Tub?
What gauge wire to use is one of the crucial factors when wiring a hot tub. This will let you determine the flow of current through the wire.
Follow a simple rule while choosing the wire gauge. Select one size bigger wire gauge than the circuit breaker used for the hot tub.
For example, if the hot tub circuit breaker is 20-amp, choose an 8-gauge wire.
Moreover, if the hot tub circuit breaker is 30-amp, choose a 6-gauge wire.
Another vital consideration is the length of the wire. The longer wire needs higher gauge cables. The reason is longer wire offers more resistance.
Last, the wire should also be adequately insulated. Hot tub generates excessive heat. It can cause a fire if the wire is incorrectly insulated. So, proper insulation is a must.
After getting the information, use the below formula:
Size of the Wire (AWG) = 75% of the total amperage
For instance, if 40 amp is the total amperage of your hot tub, you will need a 30 AWG wire.
At the same time, wire length is also a vital factor. The longer the wire is, the thicker it needs to be.
Usually, most hot tubs require a minimum of 60 ft. long wire.
So, before buying the wire for your 220V hot tub, learn the amperage and calculate according to the above formula.
What Wire Do I Need for a 50 Amp Hot Tub?
Eager to install your new 50 amps hot tub and enjoy some relaxed time? Before installing, it is crucial to know the actual wire.
A hot tub is a different appliance than other household appliances. A 50-amp hot tub needs different types of wire as it consumes more power than other electrical devices.
Generally, a 50 Amp hot tub needs a #6 AWG wire.
For this reason, a heavier gauge of wire is necessary to handle heavier loads of 50 Amps. Another important note is that wire for hot tubs is incompatible with household circuits. These wires are not engineered for home use and can lead to fire hazards.
After determining the wire type, decide on the required wire length. Here the thumb rule is to measure the main electrical circuit and hot tub distance. Then, decide on the wire length.
In most cases, at least 50 ft. of wire is necessary for a hot tub. However, it would always be best to have an additional length of wire in hand. This will be beneficial if you need to make any adjustments.
Follow the manufacturer’s instructions to have a successful and safe installation.
What Wire Do I Use for a 240 Volt Hot Tub?
A wide range of wires for a 240 hot tub is available. That doesn’t mean you can use any wire with your 240V hot tub.
First, you must know the hot tub’s ampacity to find the correct wire.
In most cases, a minimum of 40 ampacities is necessary for a 240V hot tub. However, if you are still determining what size of wire is required, always consult with a skilled electrician.
Then, understand the insulation type.
Hot tubs have 2 types of insulation: THWN and PVC.
THWN insulation type is suitable for industrial and commercial appliances. Durability is also high.
On the other hand, PVC insulation type is an ideal choice for household appliances.
Then, determine the wire gauge after identifying the wire type. Remember, the thicker the wire, the higher the gauge will be.
A minimum of 4 gauge wire is needed for a 240-hot tub.
Last Words
After reading this guide, now you know which one to choose between 6/3 or 6/4 wire for hot tub.
You should know the amps and volts ratings of these wires. Also, you can have a look at the complete guide to NM-B wiring and its uses to get the right wire for your DIY job.
However, I recommend you contact a professional mechanic. Hot tub wiring requires basic knowledge of electrical components and local codes. A professional electrician will help you make a precise decision.
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