Three phase double door DB in 4, 6, 8 and 12 way sizes — hinged outer door and inner MCB cover, for homes, shops and offices on a three-phase supply.
- Sizes of 4, 6, 8 and 12 ways — in a three-phase board the way count is usually per phase.
- Double door build: a hinged outer door with a catch in front of a screw-fixed inner cover.
- Separate MCB windows on the inner cover, each with ON/OFF arrows and a label strip for naming circuits.
- Only the MCB handles are exposed when the door is open — terminals and wiring stay behind the cover.
- Inner cover held by four screws and removed only for wiring and maintenance.
- Clean white finish on the door, inner cover and frame.
- Sold empty — the incomer, RCCB and MCBs are chosen to suit your load and bought separately.
A three phase distribution board takes a three-phase supply — R, Y and B plus neutral — and splits it into separate circuits, each protected by its own MCB. Boards like this are commonly called TPN DBs (three phase and neutral) and suit homes, shops, offices and workshops with a three-phase connection. The 4 way board in our photo has 16 numbered positions in four MCB windows.
What goes in a three phase DB
- Incomer: a four pole (TP+N) MCB, four pole isolator or 4-pole RCCB.
- Outgoing: SP MCBs for single-phase circuits, shared out across R, Y and B.
- Three-phase loads: a TP or TP+N MCB for a motor, pump or three-phase AC.
Balance the single-phase circuits across the three phases. Your electrician plans the exact layout; keep spare ways for future circuits.
Where to use it
- Homes and villas with a three-phase connection.
- Shops, showrooms, clinics and offices.
- Workshops and small factories with three-phase machines.
- Common services of apartment blocks, such as pumps and lighting.
How to install
- Plan the incomer, RCCB and outgoing circuits with your electrician, balancing the load across the three phases.
- Fix the board level at an accessible height, away from water, and bring the cables in neatly.
- Fit the incomer and MCBs on the DIN rails, connect the phases, neutral and earth as marked, and tighten every terminal.
- Refit the inner cover, close unused openings with blanking plates, label each circuit and close the door.
Three-phase work should be done by a licensed electrician with the supply switched off. The board itself does not protect anything — protection comes from the MCBs and RCCB fitted in it.
Frequently asked questions
- What does 4 way mean in a three phase DB?
- In three-phase boards the way count is usually per phase: a 4 way board typically takes four single pole MCBs on each of R, Y and B — 12 in all — with separate space for the incomer. Ask us if you need the exact count for a size.
- TPN DB, phase selector DB or phase segregated DB — what is the difference?
- A TPN DB like this one is the normal three-phase board. A phase selector DB adds selector switches so a group of circuits can be moved to a healthy phase when one phase fails. A phase segregated (7 segment) DB keeps each phase in its own covered compartment.
- Are the MCBs included?
- No. The board is sold empty — see our four pole MCBs, four pole isolators and 4-pole RCCBs for the incomer, and SP MCBs for the circuits.
- Why balance the load across the phases?
- Spreading single-phase circuits evenly over R, Y and B keeps each phase within its rating and reduces neutral current. Your electrician plans this when allotting circuits.
- Do I need an RCCB as well?
- For homes, yes: the CEA safety regulations (2023) call for a residual current device of 30 mA or less in domestic installations. An RCCB trips on earth leakage to protect people from shock, which MCBs do not do.
Buy three phase double door DBs online from Electric Market, Chennai. For site, contractor or bulk quantities, contact us for a quote.