Is Romex 6/3 the largest gauge of NM-B electrical wire?

No, there are two sizes larger than Romex® 6/3 which are 4 AWG and 2 AWG which come in a three conductor version only. Each of the 3 different sizes has 3 THHN insulated electrical wires and one bare copper bare copper ground wire. All 3 versions come with a black outer jacket.

Romex® 6/3 is the most popular type of NM-B wire excluding 14, 12 and 10 AWG circuit sizes. It is common to run a 6/3 Romex® electrical cord to a new power source that gives a new barn or garage a certain amount of power to distribute to the lights and outlets in that new area. The 6 3 wire is also a common size for powering up a new hot tub or spa inside your home.

Be careful not to use Romex® when using electricity for anything outdoors, even if it is in a duct. You will need to upgrade to either an MC cable or a UFB cable, both approved for outdoor and conduit use. UFB stands for Underground Feeder, which is also approved as underground cable without conduit or trunking.

The larger sizes of Romex®, such as 4/3 and 2/3, are used when your new garage or barn needs more power than a 6 AWG 3 conductor wire can provide. The larger the copper, the more power it provides. to the source. Once power has been applied to the new electrical box, it can be distributed to the different smaller sources that also need power.

The only difference between an NMB cable and a UFB cable is the outer jacket. The rest of the cable remains the same in terms of features. For example, both cables come with THHN wires and a bare copper ground wire. Therefore, both cables conduct the same amount of electricity. The difference comes in the amount of protection the outer jacket offers. Romex® comes with a thin PVC jacket, while UFB has a much more protective PVC jacket that surrounds each individual conductor. The NMB cable jacket can be penetrated by moisture and external gases, while the UFB jacket cannot.

It is advisable to discuss your application with your supplier and your electrician to ensure that you have sufficient power and extensive protection based on the environment in which the cable will be placed. You want to make sure you pass the inspection, which is far more important than saving a few bucks on installation costs.