DB (DISTRIBUTION BOARD)
DB – Distribution board is set of MCBs, ELCBs/RCCBs which are installed in a metal box & is used to distribute electrical power to different loads.
Classification of DB –1) according to usage, 2) according to supply,
1)Classification of DB according to usage –
- LDB (Lighting DB) – It is used to distribute power to lighting circuits, 6A power points, exhaust fans etc. It is used for maximum 6A/10A current loads.
- PDB (Power DB) – It is used to distribute electrical power /supply to power loads such as Geyser, Fridge, AC etc. All these items draw high current. MCBs of current rating 16A,20A,25A are used.
- L&P DB – When DB is use for both lighting & power loads.
- NDB (Normal DB) – It is used for normal AC supply where load is to be fed from normal power.
- UPS DB – It is used for UPS supply where load is to be fed from UPS power.
- Classification of DB according to supply –
- 3- phase DB –
A 3 Phase DB consists of one no. three phase incoming MCB and a set of single phase outgoing MCBs. A 3 phase DB can be used for Lighting & Power load. It can be arranged in two ways –
- Incomer – One TPN /4P MCB/ISOLATOR along with equal rating of ELCB /RCCB is used and outgoing– single phase MCBs – 4 nos/6 nos/8 nos/10 nos/12 nosper phase are used . Such arrangements are called 4Way TPN DB/6Way TPN DB/8Way TPN DB/10Way TPN DB/12Way TPN DB. One no. neutral bar per phase & one no. earth linkper phase are fitted in the DB for neutral &earthing wire connections of each circuit.
- Incomer – One no. TPN /4P MCB/ ISOLATOR and outgoing single phase MCBs 4 nos/6 nos/8 nos/10 nos/12 nos SP MCBs per phase alongwith SP/DP ELCB per phase are used. Such arrangements are called 4Way TPN DB/6Way TPN DB/8Way TPN DB/10Way TPN DB/12Way TPN DB. One neutral bar per phase & one earth ling per phase are fitted in the DB.
- Single phase DB –
A Single phase DB consists of one incoming and a set of outgoing MCBs. These can be arranged following way –
Incomer – One DP MCB and outgoing– 4nos/6 nos/8 nos/10 nos/12 nos SP MCBs along with SP/DP ELCB are used.
IMPRTANT TERMS –
- SP – Single Pole (only one point isolation contact where one phase is connected).Application – Switching & protection is done in one phase only.
- SPN – Single Phase with Neutral. Application – same as above.
- DP – Double Pole (Two point isolation contacts where Phase & Neutral are connected). Application – Switching & protection is done in one phase & neutral only.
- TP – Triple Pole (Three point isolation contacts where R,Y,B phase are connected). Application – Switching & protection is done in all 3 phases only.
- TPN – Triple Pole with Neutral (Four point isolation contacts). R,Y,B phase & Neutral are connectedbut protection is given for 3 phases only, not for neutral.
- 4P – Four Pole (Four point isolation contacts. R,Y,B & Neutral are isolated & protection is given for 3 phases & neutral)
- 4/6/8.. Way TPN DB – In this, each phase has 4/6/8/.. MCBs that is why 4 Way TPN DB has 12 outgoing MCBs while 6 Way TPN has 18 MCBs & so on.
- Phase– Live wire (from where current flows),
- Neutral – where current returns
- Earth/Ground – Point which is connected with earthling.
- Insulator – Material which does not allow current to flow. It is used as a support in DB.