When installing a 200 Amp service, you will need at least 3/0 AWG copper wire or 4/0 AWG aluminum or aluminum copper-clad wire. Allowable ampacity of 3/0 copper wire is 225 Amp, while the allowable ampacity of 4/0 aluminum wire is 205 Amp. 

• 2/0 AWG copper wire is not completely out of the question, but its ampacity is 195 Amp-200 Amp, which will put it at a maximum load, so using 3/0 AWG copper is a better option.
• For grounding conductors, the minimum size for is 4 AWG for copper conductors, and 2 AWG for aluminum or aluminum-copper clad conductors.
• If you plan to run cables for a long distance, you should accommodate a voltage drop of 3%. For a a 100-foot distance, you may need to upsize to 4/0 AWG copper wire or 250 MCM aluminum wire, respectively. For over a 150-foot distance, use 250 MCM copper wire and 350 MCM aluminum wire.
• You may choose to accommodate to NEC 220-2 rule that states that the maximum loading for any branch circuit is 80% of the rating. In this case, use cables with an ampacity of 250 Amps. These are 350 MCM copper and 500 MCM aluminum.
• The conduit for wire for the 200 Amp Service should be at least 2 to 2,5 inches as there are three wires running at once.

When is 200 AMP Service Enough?

200-amp service is a standard type of service for regular-sized new homes. It supports all kinds of electrical needs in a regular private home without an extremely large HVAC system. The service supports houses sized 3,000 to 3,500 square feet. These houses have HVAC systems, electric appliances, electronics, EV car charger, electronics, and modern lighting systems.

The upgrade to 200 AMP Service is necessary when you upgrade the service panel in a regular-sized private house.

When it comes to commercial buildings, 200 AMP service can support small commercial spaces, namely individual tenants in a commercial building.

200 Amp Service in commercial spaces is enough for:

• Small retail shops, offices, or cafes with limited electrical equipment
• Small workshops, studios, or warehouses 
• Tenant spaces within a larger commercial building with amp service only for the specific tenant's area

200 Amp Service in commercial spaces is not enough for entire office buildings, restaurants or commercial kitchens, offices with server rooms, and gyms.

In industrial buildings, 200-AMP service may be enough for light manufacturing facilities with limited machinery ( small clothing production) and smaller storage facilities and warehouses, but the load calculations best be performed for good results.

Types of Cables Suitable for 200 AMP Service

Both copper and aluminum cables can be used for 200 AMP service as long as size requirements are met.

Popular cables for 200 AMP service are:

1. Service Entrance SER Cable: Service entrance cables for  200 AMP service are acceptable both in copper and aluminum. They are used to connect the electric meter to the main service panel. 
2. THHN/THWN Wire: 200 Amp service allows for THHN/THWN in copper and aluminum. These individual conductors can be used inside a conduit for service entrance applications. 
3. Underground Service Entrance (USE-2) Cable: This type of cable is designed for direct burial and is used when the service entrance conductors run underground from the electric meter to the main service panel. Aluminum RHH/RHW-2/USE-2 90°C XLPE Insulation 600V and XLP USE-2 RHH RHW-2 Copper Conductor Building Wire are an option. USE-2 is suitable for all outdoor applications and direct burial applications. UF-B cables are not used for outdoor direct burial installations because they are not available in sizes needed for 200 AMP panels.