208Y/120 V three-phase wye service
A 208Y/120 V service is a three-phase, four-wire low-voltage wye service that includes a neutral. Utilities generally provide it to commercial customers. Typical sites are small commercial buildings, department stores, office buildings, K-12 schools and light manufacturing. The utility usually supplies it from a wye-wye bank of three single-phase transformers, the most popular three-phase bank configuration. It can also come from an underground padmount transformer with a four-wire wye primary and a four-wire wye secondary. Larger industrial customers usually take 480/277 V service instead, because the higher voltage carries the same power with lower current, smaller wire and lower losses. At Orange and Rockland, this service is offered only where a 208Y/120 V distribution system exists. Demand is capped at 1000 kVA with a service of no more than 3000 A, and services above 400 A must be underground. Single-phase loads should be balanced across the three phases as closely as practical. At Eversource Connecticut, three-phase 208Y/120 V network services need a main disconnect ahead of the meter (cold sequence). Some SMA backup equipment lists 120/208 V wye as a compatible grid configuration, connected to L1, L2 and N. Surge protective devices are sold with a matching 120/208 wye voltage rating.
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- sentence 3: support check: partial - Wye-wye as most popular bank and the underground padmount four-wire wye/wye supplying 208/120 are stated, but 'utility usually supplies it' from three single-phase transformers is only implied by the figure title.
- sentence 5: support check: partial - Most details match (208Y/120 area only, 1000 kVA, 3000 A, over 400 A underground, balancing), but 'offered only' is slightly stronger (restricted to areas where it 'may be available'), and overhead services over 400 A allowed up to 800 A per the passage contradicts nothing but the statement's 'must be underground' omits that overhead up to 800 A is mentioned conflictingly.
- sentence 7: support check: partial - SMA 120/208 V wye with L1, L2, N is stated, and SPDs catalogued with 120/208 wye voltage, but 'backup equipment' and 'sold with matching rating' are only loosely supported.
- sentence 7: review: partial - The SMA row backs a 120/208 V wye connection on L1, L2 and N, and the Eaton row lists a 120/208 wye SPD catalog voltage, but the passage never says the SMA equipment is backup equipment. -->