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3-Wire Or 4-Wire Service Entrance Cable: Analyzed!

Deciding on when to use a 3-wire or 4-wire SE cable is not easy. You can’t just pick one and wish it to work like a charm! Because if you don’t know about service cables, you’ll be in deep trouble.

I can tell you’re concerned about your SE cable. That’s why I’m here to answer your query and that is-

Should I go for a 3-wire or 4-wire service entrance cable?

The most used panel wiring for your meter is a 3-wire or conductor system. But on special occasions, a 4 conductor setup can be seen. Depending on your house distance, the ideal wiring can be instructed. In most cases, you’ll be able to use both 3-wire or 4-wire feeders for your beloved house.

I know you are probably curious to know more about these. That’s why I’ll cover everything about these cables here. 

Come along and clear your confusion!

Knowing Your Cables

Service cables primarily bring the electrical power from the companies to your house. Service entrance wires are mainly two types: SER and SEU. These are the most used cables for your service wiring.

One thing to mention very early on. Always maintain electrical safety guidelines before you start working with these cables. Because their SE cables can be quite dangerous.

SER has four conductors and a neutral end. On the other hand, SEU has two conductors and concentric neutral. While they differ in anatomy, both are excellent when it comes to panel feeders.

4-wire SER cables and 3-wire SEU are very good service wires for house. You can’t really go wrong with either of those. But it’s better to know about these beforehand. Otherwise, there will be some complications. 

Some Factors to Consider Before Service Entrance Wiring

Before you use these 3/4 wire service entrances, you have to know something. Service entrance wiring is very different from your typical interior wiring. That’s why you can’t confuse it with 3- vs 4-wire for 220v

If you’re clear about that, your job is halfway done. Why? Because now you’ll understand the guidelines easily. Still, there are some caveats.

3-wire sub panels generally don’t support the connection of ground and neutral electrodes. Inversely, 4-wire sub panels have to have neutral and ground connected together in a system.

Still, there might be some situations where your inspector may provide a second grounding electrode. That’s why, before jumping onto the best situations for these two wirings, you need guidance.

Are you ready to know when to use the 3-wire service entrance? If so, head on to the next segment!

Using 3-wire for Service Entrance

The moment has arrived when I tell you when to use the 3-wire service entrance cable. Whether it’s 80 amp wire or other wire, you can use service entrance 3-wires. Because they comply with the NEC codes in almost every state.

Still, you have to be careful sometimes. When using a 3-wire feeder, you can’t have any return parallel grounded path. Also, according to the 2008 NEC code, the old 3 feeders will need bonding to the neutral. After that, you can connect it with your GEC.

You can even use a 3-wire feeder in replacement of a 4-wire meter base. But there has to be proper bonding and grounding.

If you are planning to pick up some 3 wire cables, here are my top recommendations:

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I think you are now well aware of 3 wire systems. It’s time for the 4 wire setup to come into action!

Using 4-wire Setup for Service Entrance

Like 3-wire feeders, 4-wires can also be used on many occasions. When the situation involves installing meters with a disconnect, it’s better to use 4 wires. Similarly, you can also use these types of wiring inside the interior.

Another use case of 4 feeders is when you have a mobile home. There is no other option for you when you’re using it for your portable house. Then, you won’t have any problem with your in-house 200 amp wire anymore!

Otherwise, there can be power outages, misconnection, or other complications. To avoid such adverse conditions, always remember to see the NEC guidelines.

Are you looking for the best deals on 4 wires setup? Have a look at these offerings:

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You’re now fully equipped with all the knowledge about these service entrance cables. All that’s left for you is to choose one depending on your situation.


Question: What size wire do you need for a 200 amp service?

Answer: Your 200-amp will require a #2/0 AWG copper or #4/0 AWG Al wiring. These are for only the installation and you’ll need 1.5 inches of wiring. If you plan for underground service, you’ll also need a 40/80 PVC conduit. But you can easily work with 2/2.5 inches wiring in a 3-wire conduit.

Question: Is 4-wire service entrance cable more costly than 3 wire?

Answer: Depending on some factors, 4 wire is relatively more expensive than 3 wire. But not all SER 4 wire service cables are expensive. If you want to go for a cheaper option, Aluminum wires will be better. Copper SE cables have higher production costs and better overall quality.

Question: Can type SE cable be Installed in the Interior of a building?

Answer: Yes, you can definitely use type SE cable in the interior of your building. These types of cables are frequently installed inside buildings. They provide an ample amount of heating and cooling elements. Along with that, the cables abide by NEC Article 334 except for the ampacity measurements.

Bottom Line

I hope you now have a clear idea about 3-wire or 4-wire service cables. Always remember to check the NEC codes before you start wiring.

If you have any questions regarding service entrance cables, feel free to let me know.

That’s all from my side. Best of luck with your service entrance cables!