MCB Box Size List, and How Many Ways Your Home Needs

MCB box size list: the short answer

An MCB box is sized by its number of ways, not by its measurements: one way is one position for a single pole MCB. Our MCB box size list runs from a 1 & 2 way PVC surface box at ₹40 MRP up to an 18 way board, with double door distribution boards from 4 to 16 way and three-phase TPN boards from 4 to 8 way.

Every size and MRP below is from our current catalogue. We make these boxes, and the 10 kA MCBs that go inside them, at our works in Marol, Andheri East, Mumbai, under the VIYONA name.

The way to choose a size is the order an electrician works in: count the circuits in the house, add two or three spare ways, and buy the box that holds that number. Which brand to buy is a separate question, answered in our guide to the best MCB box brand in India.

What sizes do MCB boxes come in?

MCB boxes come in way-counts, and ours run 1 & 2 way and 3 & 4 way for PVC surface boxes, 2–4, 6–8, 10–12 and 16–18 way for the S.P.N. white line box, 4, 6, 8, 10, 12 and 16 way for double door distribution boards, and 4, 6 and 8 way for TPN double door boards.

The four families do different jobs. The PVC surface box holds one to four MCBs on a finished wall. The S.P.N. white line MCB box is the everyday single-phase board, from ₹380 for 2–4 way. The MCB distribution double door adds an outer door, from ₹750 for 4 way. The TPN boards are for a three-phase supply only.

VIYONA 374 is a 16–18 way S.P.N. white line MCB box with an MRP of ₹950, the largest size in our list. VIYONA 371, the 2–4 way size, is ₹380.

What does one way mean in an MCB box?

A way is one outgoing position in an MCB box, the space one single pole MCB occupies, so an 8 way box holds eight single pole MCBs, or fewer if some of them are double pole, because a double pole MCB takes two positions side by side and counts as two ways.

So count positions, not devices. A single pole MCB such as our VIYONA 401 takes 1 way. A double pole MCB such as the VIYONA 411 takes 2 ways. An RCCB, which we do not make, also takes more than one way, so ask your electrician to count it in.

The main switch, or incomer, needs a word of its own. On some boards it has a space of its own beside the outgoing ways; on others it sits on the same rail and uses ways from the count. Check the incomer space before you settle on a size. Our worked examples count single pole outgoing MCBs behind a separate incomer, as our house electrical layout guide does.

MCB box size chart: double door distribution boards

Our double door range comes in six sizes, one way-count each, which makes it the simplest part of the list to order from: 4 way, 6 way, 8 way, 10 way, 12 way and 16 way.

VIYONA 385 is a 12 way MCB distribution double door board with an MRP of ₹1,210, the size our layout guide uses for a typical 2BHK. VIYONA 381 is the 4 way size at ₹750, and VIYONA 386 the 16 way at ₹1,410.

For dealers, the catalogue lists the double door range under HSN 85371000 and the S.P.N. white line box under 85362030. We sell in full boxes only; ask the office or your dealer how many boards come in a box for a given code. The range is shown on our MCB distribution box page.

What is the MCB box size in mm, inches or feet?

We do not publish MCB box dimensions in mm, inches or feet, because the outside size of a box with the same way-count varies from maker to maker and model to model, so boxes are ordered by way-count and type, and our office gives the measurements for a specific code when you ask for them.

A size chart in mm from another maker’s leaflet will not tell you whether our box fits. What decides the fit is the wall recess for a flush box, or the clear wall space for a surface one, measured against the actual box.

There is no separate MCB box size list PDF; the table on this page is the list, with code, type, way-count and MRP. Our full catalogue is on the e-catalogue page.

So the practical order is: settle the way-count with your electrician, pick the type, then ask the dealer or our office for the dimensions of that one code before the mason cuts the wall for a flush box.

How many way MCB box for a 2BHK?

A typical 2BHK takes a 12 way MCB box, as common practice: about ten outgoing circuits, two for lights and fans, two for general sockets, one for the kitchen’s heavy points, one for each of three ACs and one for each of two geysers, plus two spare ways for later.

That is the same worked example in our which MCB for home guide and our layout guide, and we keep the numbers identical on purpose. In ways: 2 lights and fans 2 sockets 1 kitchen 3 ACs 2 geysers 2 spare, behind a double pole incomer.

In our range that is the 373: 10–12 way S.P.N. white line box at ₹620, or the 385: 12 way double door board at ₹1,210. Fewer ACs can mean 8 or 10 way; double pole AC MCBs mean more.

How many way MCB box for a 1BHK or a 3BHK?

As common practice, a 1BHK with one bedroom AC, one living-room AC and one geyser comes to about six circuits and an 8 way box, and a 3BHK with four ACs and three geysers comes to about fourteen circuits and a 16 way box, each count including two spare ways for later.

The 1BHK count: 1 lights and fans 1 sockets 1 kitchen 2 ACs 1 geyser, plus 2 spare. That fits the 372: 6–8 way white line box at ₹480 or the 383: 8 way double door at ₹995.

The 3BHK count: 3 lights and fans 3 sockets 1 kitchen 4 ACs 3 geysers, plus 2 spare. That fits the 374: 16–18 way white line box at ₹950 or the 386: 16 way double door at ₹1,410.

SPN vs TPN: which MCB box size list applies to you?

Use an SPN box if your home has a single-phase supply, which most Indian flats do, and a TPN box only if the meter and the electricity bill show a three-phase supply, because SPN carries one phase and a neutral while TPN carries three phases and a neutral.

The supply decides the type, and then the way-count decides the size. Our S.P.N. white line box is the single-phase board. Our TPN boards are double door: VIYONA 387 is a 4 way TPN double door board with an MRP of ₹2,620. The 388: 6 way TPN is ₹3,050 and the 389: 8 way TPN ₹3,350. Two TPN boards with TV and telephone space, 390 and 391, are also in the catalogue; ask our office for their way-count and MRP.

A TPN board costs more because it distributes three phases, and its ways are counted per phase by the board’s own layout. Our MCB box brand guide explains SPN, TPN and phase segregated boards in more depth.

Single door or double door MCB box?

A single door MCB box has one cover over the breakers, while a double door box adds an outer door in front of that cover, keeping the MCB handles reachable but closed off, and the choice is about where the board sits and who can reach it, not about how many ways it has.

In our list the double door is a separate range: the MCB distribution double door, 4 to 16 way, and the TPN boards. The S.P.N. white line box and the PVC surface boxes are listed without a door description, so ask the dealer to show you the box before you choose.

A double door board suits a passage, a kitchen wall or anywhere children can reach. A white line box costs less at the same way-count: 10–12 way is ₹620 against ₹1,090 to ₹1,210 for 10 or 12 way double door.

Some brands, such as Hager and Siemens, state a higher IP rating for their double door boards than for single door. Our brand guide sets out what each maker states; we do not quote an IP rating for our own boxes.

Which MCB box size gives the lowest price per way?

The larger the box, the less each way costs: our 4 way double door board works out at about ₹188 per way and the 16 way at about ₹88, while the S.P.N. white line box falls from about ₹95 per way at 2–4 way to about ₹52 at 10–12 way.

First, spare ways are cheap: moving up one size usually adds two to four ways for less than a second box would cost later. Second, the white line box is the lower-cost route per way at every size, while the double door range costs more for the outer door.

Between 10–12 and 16–18 way white line the cost per way is flat, about ₹52 against ₹53, so wall space decides.

PVC surface MCB box sizes: 1 to 4 way

For one to four MCBs on a finished wall, our PVC surface MCB box comes in a 1 & 2 way size at ₹40 MRP, a 3 & 4 way size at ₹90, and a Royal 1 & 2 way at ₹66, for a single circuit or two away from the main board.

VIYONA 375 is a 1 & 2 way PVC surface MCB box with an MRP of ₹40, the smallest and lowest-priced size in our list. The 1 & 2 way PVC Royal MCB box (VIYONA 377) is ₹66, and the 376: 3 & 4 way is ₹90.

Common uses: a local cut-off for a geyser, a water pump or an outdoor light, or a pair of MCBs for a shop counter or a single room fed from the main board. A surface box screws onto the wall and can go up at any time, so it suits rewiring jobs where the plaster is already finished.

A small box is never a substitute for the main board. The circuit feeding it still starts at an MCB in the distribution board.

What goes inside the box, and how to order

The box is only the housing. Inside go the 10 kA MCBs: VIYONA 401 is a 6–32A single pole 10 kA MCB with an MRP of ₹145, packed 12, and VIYONA 411 is the double pole at ₹350, packed 6. The 40A DP incomer, VIYONA 412, is ₹435. All are made to IS/IEC 60898-1. Which rating goes on which circuit is in our MCB for AC and MCB for home guides.

For a single point at a switch board, the KEMPS TinyTrip modular MCBs are K225 ₹295 single pole (10A to 32A) and K226 ₹625 double pole. They add a local cut-off; they do not replace the board.

At MRP, ten 401s (₹1,450), a 412 incomer (₹435) and a 373 box (₹620) come to ₹2,505; with a 385 double door board instead, ₹3,095. The MCB protects the house wire behind it, so the cable comes first; an isolator only switches and protects nothing.

We sell through 500+ dealers, in full cartons; there is no online shop. Order by phone, at a dealer or by visiting.