Guides
Guides 19/10/2026 INVENTĀRS
What socket drive squares mean
Two numbers get glued together: the drive square (1/4, 3/8, 1/2 inch) and the opening in millimetres (9, 10, 14 mm). The first is which ratchet the socket sits on. The second is the nut. This page keeps them apart. MarkRead it asMistake 1/4, 3/8, 1/2Drive squareThinking 1/2 means “a 13 mm socket” 9 mm, 10 mm, 14 mmWrench openingForcing 1/4 onto a 1/2 ratchet with no adapter 6- vs 12-pointHow many flats hold the nut12-point “always better” ImpactMade for an impact wrenchA chrome socket in impact What each square is for The inch size measures the drive — the square the socket sits on. It is ..
Guides 19/10/2026 INVENTĀRS
DIN energy meters
A DIN energy meter in the board shows how many kWh a circuit or a tenant takes. It is not the DSO billing meter at the incomer and not an LBN 53.4 acceptance test — see acceptance tests. This page is how to read the card: phases, current, MID, S0, CT. LBN 261-15 does not specify a meter model. P.8³: dwellings with incomer protection above 32 A are three-phase. No live CT wiring steps. FieldMeaningMistake 1 ph. / 1P+NSingle-phase circuitUsing it on a three-phase site “because 40 A is enough” 3 ph. / 3P / 3P+NThree phases; N only if the card says soOne 1-phase meter on one phase “to see the ho..
Guides 19/10/2026 INVENTĀRS
DIN rail and distribution-board accessories
Once the protection scheme is clear, the remaining question is where the devices actually sit. A modular consumer unit, an empty metal box with a mounting plate and a loose DIN rail are not the same product. This guide helps you choose the enclosure, rail, blanking strip and door. Device ratings still belong in the board bill of materials — this page does not retarget “distribution boards price”. Information, not a design. LBN 261-15 p.55: installation under a certified specialist. P.17: equipment must withstand site conditions. Conformity to LVS EN 61439 sits with whoever assembles the board ..
Guides 18/10/2026 INVENTĀRS
Terminals and busbars in the board
In a board, conductors are not joined “wherever it fits”. There are at least three different parts: N and PE bars, a phase comb busbar between MCBs, and DIN terminals for outgoing conductors. This guide helps you read cards and compile a materials list, not install connections yourself. LBN 261-15 does not name a WAGO or Hager model. Point 55: installation under a certified construction specialist. Isolated ferrules are almost unpublished in our range (more sit unpublished in BoL), so we do not recommend ferrule SKUs here. Count modules first in the board bill of materials. MCB In and curve: c..
Guides 18/10/2026 INVENTĀRS
Electrical installation acceptance and tests
Building electrical installations are taken into service under construction law. LBN 261-15 point 53 lists what is attached to the acceptance act if the relevant work was done. This guide is for a professional audience and the client: what is documented, what is measured and who may do it. It is not a guide to measuring live, bypassing protection or “energising the site” yourself. Point 53.4 (checked likumi.lv 18 Oct 2026) requires approved reports on: conductor/cable electrical resistance tests; full impedance measurements of the phase–neutral loop; leakage resistance tests of earth-electrode..
Guides 18/10/2026 INVENTĀRS
IP protection and cable glands
Enclosure IP and the cable entry together decide whether a joint stays dust- and water-protected after assembly. A common mistake: buy an IP65 box and drill a hole without a matching gland. This guide is how to read IP and gland range from the card, not how to guess millimetres. LBN 261-15 point 17 requires equipment to withstand the environmental conditions at the place of installation (Annex 3) — that is not “IP65 on every outdoor box”. On the cardMeaning (IEC 60529)Example IP55 / IP56Dust-protected + water jet / stronger jet as declaredGewiss GW44218 — IP56, internal 240×190×160 mm, smoot..
Guides 18/10/2026 INVENTĀRS
CEE industrial sockets: 16 A, 32 A, 4P and 5P
A CEE industrial socket (IEC 60309, often P17, Hypra, Pratika) is a round connector with a fixed protective-contact clock position. It is not a household Schuko and not an Italian P11. This guide is how to read 16 A / 32 A, 4P / 5P, 6h and IP from the card, and where LBN 261-15 touches outdoor sockets. Information, not a design. We do not claim two devices “fit together” unless current, voltage, poles and clock position match. ParameterRead on the cardCommon mistake Current16 A or 32 A (63 A is another size)Expecting a 16 A plug to fit a 32 A socket Poles3P, 4P (often 3P+E here) or 5P (3P+N+..
Guides 18/10/2026 INVENTĀRS
Motor protection and contactors
A motor circuit usually has three jobs: overload protection, short-circuit protection and switching. They can be combined or split. A common mistake: fitting a household C-curve MCB and assuming the motor is protected. Information, not a design and not a start-up procedure. Motor circuits are designed and set by a certified specialist. Labels: LBN, standard, manufacturer recommendation. Three devices, three jobs DeviceWhat it doesWhat it does not do alone Motor-protective circuit breaker (MPCB, MMS)Thermal-magnetic protection: overload + short circuit; often an adjustable thermal setting in..
Guides 18/10/2026 INVENTĀRS
Choosing an MCB: B, C, D, In and Icn
A miniature circuit breaker (MCB) in a dwelling board protects the cable and equipment against overload and short circuit. Search results often show universal tables “B for homes, C for workshops, D for motors”. Those tables are not a requirement of LBN 261-15 and they do not replace a design. This guide explains the curve, rated current and breaking capacity, and which inputs you need before you order a device. This is information, not a design. Installations are designed, installed and tested by certified specialists. Labels: LBN — mandatory, standard — an applicable standard, recommendation..
Guides 18/10/2026 INVENTĀRS
Surge protection in the distribution board
Overvoltage reaches a board from a nearby or line lightning strike and from switching in the network. It lasts microseconds but can damage boiler controls, a heat pump, a router or a TV. A surge protective device (SPD, "surge arrester") diverts this impulse to earth. This guide explains how to choose the SPD type and scheme and what to check in the specification. This article is not a connection guide. An SPD is installed by an electrician according to the design and the manufacturer's instructions. What LBN 261-15 says Point 25.4: protection against lightning current and overvoltage is one ..