Installation acceptance: documents, LBN 53.4 tests and instruments

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 loops; and bonding resistance tests between earth electrodes and parts to be earthed. That is four kinds of report, not one megohmmeter reading. The chapeau of point 53 says “if the relevant work was done” — do not spread every item onto every small alteration.

Point 54: insulation resistance is checked before acceptance. Minima are in Annex 6 Table 2 (wording of Cabinet Regulation No. 355). As fully readable on likumi.lv on 18 Oct 2026: up to 50 V SELV/PELV — 250 V test, > 0.5 MΩ; up to 500 V except SELV/PELV — 500 V test, > 1.0 MΩ; above 500 V — 1000 V test voltage; the MΩ cell of that third row was not unambiguously readable in our extract, so we do not invent it — read the table on likumi.lv.

Point 55: installation under a certified construction specialist; the tests in 53.4 are done by a certified electrical specialist certified by a Latvian-accredited body competent under LVS EN ISO/IEC 17024. The client does not replace that person with “a friend with a tester”.

Cabinet Regulation No. 238 (fire safety) points 56–58 and 62 is a different regime (periodic inspection, thermal imaging of boards in stated cases, no home-made protective devices). Do not mix it with first acceptance under 53.4.

Instruments in the range are for a competent specialist. We do not say which probe goes where. Insulation: UNI-T UT526 (250 V, 500 V, 1 kV on the card), UNI-T UT501B, UNI-T UT511, UNI-T UT502A. Clamp earth helper: UNI-T UT278A (20 A, 32 mm on the card) — not an automatic 53.4 certificate. Fluke 115 is a general multimeter, not a 500 V/1 kV insulation test. UNI-T UT15C indicates voltage. UNI-T UT07B-EU is a 230 V socket checker — it does not replace 53.4 reports. CAT ratings from the card only; we do not claim a model is valid for every distribution-network measurement.

No live-work steps, no RCD bypass “so we can measure”. If an RCD trips often, that is a fault — residual current protection, not a tester workaround. Instruments: digital meters. Board list: bill of materials.