Count the positions that are energized, and only those. A meter section with its breaker pulled, its bus lugs capped and a gasketed blank over the socket is not a disconnecting means. It adds 0 to the NEC's ceiling of six service disconnects. The same section with its breaker still bolted to the live bus adds 1, because it is ready to take conductors again. A 1200 A bank rebuilt with two 400 A and two 200 A meter-mains therefore lands at 4 disconnects. Its mains sum to exactly the bus rating. Both numbers sit at their practical end, which is the case for deleting the spare sections rather than shipping sockets that invite a seventh disconnect.
What the NEC six-disconnect rule says
The NEC lets a building carry one service disconnecting means. In place of that single switch or breaker, it allows up to six when they meet its grouping conditions. A meter bank fed by one service is the everyday case: every meter-main breaker or fused switch is one disconnecting means, so the bank holds at most six energized positions.
The grouping conditions are practical:
- the disconnects sit together at one location, in one or more adjacent enclosures;
- each set of service conductors lands on its own disconnect;
- each disconnect is marked as a service disconnect and operates independently;
- each one is rated for the load it carries.
The meter itself stays out of the count: it measures, it never opens the conductors. Tenant breakers downstream of each meter sit on the feeder side and stay out too. A bank with eight or twelve sockets is not one service with twelve disconnects. The NEC permits a separate service for each occupancy of a building, so each of those sockets stands as that tenant's one allowed disconnect. A single-service bank of this size stays under the plain six-position ceiling.
What a blanked-off section is worth
The line side of each breaker is fed straight off the service bus, the same way the line side of a separate disconnect enclosure stays live. A blank is worth 0 in the count only when three things are true: the breaker is out of its cubicle, the bus lugs are capped or insulated, and a gasketed blank plate closes the socket. The utility then records the position as dead space rather than a service.
Leave the spare breaker bolted in with nothing on its load lugs, and you have left a live disconnecting means in the bank. Count it as 1 of the 6. One bolted connection decides whether the finished bank passes or sits one handle past the ceiling.
The rebuild in numbers
| Layout | Energized disconnects | Mains sum | Verdict |
|---|---|---|---|
| Existing bank: 5 sockets of the smaller size | 5 of 6 | 1000 A | Legal, one socket spare |
| Add a 400 A section, keep 3 live spare breakers | 7 | 1800 A | Fails: 7 disconnects, mains at 150% of bus |
| Same four meters, 3 sections made dead | 4 | 1200 A | Legal, mains equal the bus rating |
| Clean rebuild: spare sections deleted | 4 | 1200 A | Legal, nothing left to fill |
Run the ampere check the way the bank's listing does. The bus is rated 1200 A, and the mains are what load it, so their sum stays at or under that figure. Two 400 A meter-mains contribute 800 A and two of the smaller units contribute the remaining 400 A: the rebuilt bank sits at exactly the bus figure, with every ampere spoken for. Filling one dead blank later would put 1400 A of mains on that bus. Filling all three would reach 1800 A, 50% over. The disconnect count behaves the same way: 4 energized positions is legal today, and 7 is one past the ceiling.
Why deleting the spare sections wins
Order the rebuilt bank as three sections: one carrying the two 400 A meter-mains, two carrying the pair of smaller units. That is 4 sockets, 4 handles and mains equal to the bus rating, with no socket left to fill. Growth past this point means a new bank or a new service, which brings the utility and an inspection with it. That friction is what stops a quiet seventh disconnect from appearing two tenants from now.
It is also the honest answer to leaving the blanks and hoping the next crew reads the code first. A blanked socket is an invitation; a missing section is a wall. If the utility's standard layout forces a spare position on you, make it dead: breaker out, bus lugs capped, gasketed blank plate fitted, utility seal applied. Label each blank 'SPARE - NOT ENERGIZED' and card the door with the number of energized positions, so the six-count is obvious at the final inspection.
The physical checks on the finished bank
- Handle height. NEC 240.24(A) keeps the center of the grip of the highest operating handle, in its highest position, within 2.0 m (6 ft 7 in) of the floor or working platform. A taller section stacked on top is what breaks that line, so check the finished height before ordering. The enclosure mounting guide turns the height and clearance numbers into a mounting plan.
- Working space. NEC 110.26(A) asks for at least 3 ft (900 mm) of clear depth in front of the bank at 0-150 V to ground in Condition 1, 30 in of width or the bank width, and doors that swing 90 degrees. Bollards keep the parking lot out of that space.
- Bonding. NEC 250.96(A) requires the bank's metal parts, each added section included, to be bonded together so they safely conduct the fault current likely imposed on them. The grounding and bonding guide covers the connections, and grounding electrode conductor routing to multiple service disconnects covers the supply side.
- Weather. An outdoor bank is rain, sleet and snow rated, Type 3R in NEMA 250 terms. Every blank plate seals to the same level, and each section-to-section joint keeps its gasket. Any hole you field-cut takes a listed fitting of matching rating; what drilling does to an enclosure rating explains what a plain hole costs.
These type numbers are manufacturer ratings measured against the NEMA 250 and UL 50E test setups, not UL listings. The bank's sections come from the service-equipment maker under that maker's own listing.
What goes on the drawing and the order
- The bank layout: three sections, mains of 2 × 400 A + 2 × 200 A, bus rating 1200 A, zero spare sockets. Blank kits appear only where the utility's standard section forces one.
- The one-line: send the utility the section layout, the mains and the bus figure before any section is ordered, so the final service arrangement carries their sign-off.
- The pad: sized for the bank plus 3 ft (900 mm) of clear depth in front, with the highest handle under 2.0 m (6 ft 7 in).
- The compartments beside it: the meter bank stays listed service equipment from its maker; our work sits next to it. Tenant branch gear, telecom or lighting controls go in their own boxes, built to your width, height, depth and cutouts. At a salt-air or de-icing site, spec 316L: 304 pits under chloride deposits even at room temperature, and chloride stress-corrosion cracking starts near 60 C (140 F), a temperature a sunlit metal wall can reach in summer. Those boxes are rated NEMA 4X / IP66 by the manufacturer; not UL listed. A custom compartment starts when you approve the drawing and is delivered in 10 business days.
The decision, stated once more: a dead blank counts as 0, an energized spare counts as 1, and six energized handles on the full bus is where this bank ends. Browse custom stainless enclosures or filter the stainless enclosure size finder by grade and size for the compartments you add beside it.
Catalog dimensions to compare
Compare these catalog dimensions with your component layout. Open each enclosure for its rating, material and usable space, then check those specifications against your application.
| Enclosure | Material | Outside H x W x D / display | Rating |
|---|---|---|---|
| 12 × 10 × 6 in | 304 stainless | 12 x 10 x 6 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 20 × 16 × 8 in | 304 stainless | 20 x 16 x 8 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 24 × 20 × 8 in | 304 stainless | 24 x 20 x 8 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
Questions
Do blanked-off meter sockets count against the six-disconnect rule?
Only when they are energized. A socket with the breaker removed, the bus lugs capped and a gasketed blank plate fitted counts as 0 of the six allowed service disconnects. The same socket with its breaker still bolted to the live bus counts as 1, because it can take load conductors again without any utility involvement. Six energized positions is the ceiling for a bank on one service.
How many 200 A meters fit on a 1200 A meter bank?
Six, and the numbers agree from both sides. Six mains of that size give 6 × 200 A = 1200 A, exactly the bus rating, and six meter-mains is the disconnect ceiling for a single service. Replacing two of them with 400 A units keeps the sum the same but spends four sockets, so each bigger main costs a socket of future growth.
What enclosure rating does an outdoor meter bank need?
Type 3R is the outdoor service-equipment rating: under NEMA 250 it keeps rain, sleet and snow off the live parts. It is not a hose-down rating; a washdown site needs Type 4 or 4X. Every blanked socket takes a gasketed blank plate of the same rating, and each section-to-section joint keeps its gasket so the added section seals like the original.
Can a future tenant legally fill the blanked sections?
Not on a bank built like this one. Three filled sockets would lift the mains 50% past the bus rating and raise the disconnect count from 4 to 7, one past the NEC's six. A tenant who genuinely needs more service gets a new bank or a new service, with the utility and the inspector involved from the first drawing.
