PD Cable Duct

IET Guidance Note 6, 10th Edition, section 2.10 | IET Guide to Cables and Cable Management, section 8 | ENA TS 12-24 (duct class and duct size range), BS EN 61386-24 (N450 and N750 mechanical class), ENA ER G87 (building entry) and ESQCR 2002 (marking, screening, records)| DNO and IDNO adoptable duct tables: UK Power Networks, SP Energy Networks, Northern Powergrid, NGED, SSEN, ENWL and the IDNOs | ERA quad-bundle current ratings

18/10/2026 (3.14.1): Only wording is corrected in this release. On UK Power Networks 11 kV runs, the wording now states that ECS 02-0019 v15.0 Appendix A.3 lists 95, 185 and 300 mm2 single-core cables only as three in one duct, with no figure for one cable in its own duct. The minimum applied, 100 mm or 125 mm for 300 mm2, is unchanged. Free visitors are no longer referred to My Projects. The UK Power Networks note no longer describes the two 150 mm CHECK figures as sizes applied. No duct size, duct count, cover or factor changed. Re-check saved reports. 18/10/2026 (3.14.0): The tool is now PD Cable Duct. The free version is limited to one run in the trench; more runs come with the Engineering Toolkit. Saved work is never deleted. On UK Power Networks routes (ECS 02-0019 v15.0, EDS 08-2100 v11.2), 33 kV minimum cover is 900 mm except on agricultural land; low voltage mains above 35 mm2 and services under a carriageway need 125 mm ducts. Automatic depth of lay can be deeper and depth factor (Cd) lower. A new CHECK line names Belden FI3D006R9 and Belden 8471, whose data sheets state indoor use only. Re-check saved reports. 16/10/2026 (PD Cable Database 1.0.3): six FP200 Gold cables have Prysmian's current figures: smaller diameters for 2-core 1.5 and 4, 3-core 2.5 and 4, 4-core 2.5 mm². Steel wire armoured (SWA) 3-core 25 mm² is 23.6 mm, not 25.5 mm. A run sized automatically can need the next size down or one duct fewer, never the reverse. A duct chosen manually can need fewer ducts or no longer be too small, never more ducts or newly too small. Bending radii can be smaller, never larger. Re-check runs with these cables: reopened saved reports have the new figures and no note of the change. 15/10/2026 (3.13.0): Minimum cover is now the operator's own figure, even below Street Works UK Volume 1 (2023) Table 1, for National Grid Electricity Distribution (except 11 kV on a footway or verge: 600 mm) and SP Electricity North West at low voltage and 11 kV. In 4,867 test cases it is lower in 70 and higher in 44 (SP Energy Networks 33 kV, 775 mm, CAB-15-003, 2007). New NOTE and CHECK lines name conditions not checked. No bending radius or pulling tension is shown at 11 kV or 33 kV. Duct sizes, counts and grouping factors are unchanged. Re-check saved reports. 14/10/2026 (3.12.0): ECS 02-0019 v10.0 Appendix A.4 is now also read by conductor size on UK Power Networks 33 kV runs: 630 mm2 cables set to "up to 500 mm2" get 225 mm (A.4 gives 190 mm). Cover is measured to the highest duct; minimum cover is never below Street Works UK Volume 1 (2023) Table 1. In 4,066 test cases, 69 designs now fail on cover; depth factor (Cd) is lower in 431. Manually chosen sizes are checked against the minimum. Lines of over 64 cables can need more ducts. Bending radius is larger in 2,774 cable rows. Re-check saved reports. 11/10/2026 (3.11.1): FP400 and FP500 now count as armoured: the bend radius is calculated at 6x the overall diameter (Institution of Engineering and Technology On-Site Guide, BS 7671:2018+A4:2026, Table D5). It was 4x for 12 FP400 sizes (1.5 to 16 mm²) and all 6 FP500 sizes. Prysmian's FP400 8D (8x) is given beside the 6x and takes precedence: 176 mm against 132 mm for 10 mm² 3-core (22 mm). For shaped conductors, check the data sheet (Cable handling note). Duct sizes and other cables' bend radii are unchanged. Re-check FP400 and FP500 runs: reopened saved reports have the new figures. 11/10/2026 (PD Cable Database 1.0.2): 24 FP400 cables have Prysmian's current figures. Diameters are larger for 3-core 1.5 to 16 and 35, 4-core 1.5 to 35 and 240 mm²: a run sized automatically can need the next size or one more duct; a duct chosen manually can now be too small or need one, two or more extra ducts. Diameters are smaller for 3-core 70, 4-core 70 to 185, 300 and 400 mm²: a chosen duct can need fewer ducts or no longer be too small. Bending radii change. Re-check FP400 runs: reopened saved reports have the new figures and no note of the change. 11/10/2026 (PD Cable Database 1.0.1): the eight aluminium wire armoured (AWA) cables have Eland Cables' 0.6/1 kV figures, not 1.9/3.3 kV; the other 135 are unchanged. From 150 mm² up, diameters are 1.1 to 4.2 mm larger: the same duct is fuller, the minimum bending radius is larger, a run sized automatically can need the next duct size or one more duct, and a duct chosen manually can now be too small. AWA-120-1c is 0.8 mm smaller and its bending radius 5 mm smaller. Re-check AWA runs sized before this release: reopened saved reports have the new figures and no note of the change. 30/09/2026 (3.11.0): UK Power Networks 33 kV runs can be set to three single-core cables per duct, with a 150 or 190 mm minimum by conductor size (ECS 02-0019 v10.0 Appendix A.4). UK Power Networks 50 mm service and 125 mm 11 kV ducts are labelled Project Design (PD) practice. For the National Grid Electricity Distribution derating rule, the source line now names only the network operator. The check line states the current issue of EDS 08-0143 could not be found. The page no longer scrolls sideways at 294 px. Where the choice is not made, no duct size or result changed. 30/09/2026 (3.10.1): UK Power Networks low voltage mains in 100 mm ducts now get an amber check: EDS 08-0143 v2.0, for supplies above 100 A per phase, requires at least 125 mm under a hard standing (clause 5.2.1). The check line states that ECS 02-0019 v10.0 (2015) was read and v14.2 (2024) was not. The tool's wording names PD Cable Database as the source of its cable list and states when highway authority agreement is needed. It states that, as PD practice, the larger of the two distances is kept where two different services meet. No duct size or grouping factor changed. 29/09/2026 (3.10.0): some grouping factor values fall, because the clearance is now measured between duct outsides and every working duct in the trench is counted. Earlier ratings may need re-checking. Bend radii to the Institution of Engineering and Technology On-Site Guide (BS 7671:2018+A4:2026), Table D5, are now 6x for single-core armoured and 8x for Waveform. FP600 cables now count as armoured, with bend radii and fill from the corrected cable list. Re-check private-route runs where cables share ducts: a duct is now added where one was over 45% full. A spare duct is no longer forced at 0%. Duct sizes are unchanged. 26/09/2026 (3.9.0): the printed report is now readable, apart from the labels on the trench positioning and duct section drawings. Up to 3.8.1, each page was shrunk to fit one A4 sheet, so almost all text measured under 6 pt. In the ten cases checked, the report now prints on 3 to 5 pages instead of 2, all text outside the drawings measures 8 pt or more, and every page is numbered. The drawing labels are still under 7 pt, the smallest 4.2 pt against 1.9 pt in 3.8.1; a new print layout for both drawings is planned for a later release. Every check line shown in the tool is now printed, not only DUCTS SIZED or REVIEW NEEDED. The tool name in the header bar is now the page's main heading (h1) and looks as before. The wording shown in the tool, the exports and the report emailed to free users are unchanged. A new automated check of the printed report (606 checks) passes on 3.9.0 and fails on 3.8.1; the 1,993 scenarios in each tier were re-run with no difference; the look and every control were checked again; no size, count or factor changed; verified live after upload. 26/09/2026 (3.8.1): each line that cites a source was read against it. The ENA ER G87 lines now use G87's verb, should, and give both options: a draw pit or a 900 mm minimum radius slow bend. The ESQCR line now gives the requirements of Regulations 13, 14 and 15 and, from the 2002 DTI guidance, the order of preference for marking and protection. The UK Power Networks standard is now cited as ECS 02-0019. The single-core arrangement lines cite BS 7671 Reg 521.5 in place of 523.6, and the Appendix 10 line says the current sharing may be more like 70/30 than 50/50. The printed network list and Cover to crown box have no dashes, and the printed spare line is in plain words. The green for a pass, the amber for a point to check or a warning, and the grey for a neutral mark are now darker, so that any white text on them meets the 4.5:1 contrast that the Web Content Accessibility Guidelines 2.2 require at level AA for text of 12 px; this change applies only to the colours, not to any calculation, result, wording or layout. The 1,993 scenarios were re-run in both tiers with no difference; a new check of the changed lines fails on the 3.8.0 build; the look and every control were checked again; no size, count or factor changed; verified live after upload. 26/09/2026 (3.8.0): the tool now looks like the PD Power Distribution tool, with the same font and colours. The Start again button is now in a dark header bar with the tool name and version. The coordination drawing, the printed report and the detailed duct section in the exports are in the new colours, with the NJUG service colours unchanged. The panel for saving and exporting, below the results, keeps its present colours for now. Apart from the new colours and the header bar, the wording shown in the tool, the text, dimensions and figures in the drawing, the printed report and the exports are unchanged. The report for two cases was printed to PDF from 3.7.4 and 3.8.0 and compared: two pages each, the same text and font sizes, and every word within 0.5 pt of its place. A new automated check of the look (53 checks) passes on 3.8.0 and fails on the 3.7.4 build; the 1,993 scenarios were re-run in both tiers with no difference; the wording check added in 3.7.4 was re-run over every program file, 4,173 checks, and nothing was found; no size, count or factor changed; verified live after upload. 15/09/2026 (3.7.4): the wording in the tool, in the report, in the help and in the notes written inside the program code was revised in plain UK English, and the duct is now described by its internal diameter throughout. The tool now states that an adoptable route always includes at least one spare duct, that extra depth reduces the rating, that single-core cables on AC need a defined arrangement, and that the cable sizing is done separately. A new automated check reads every program file and 4,157 tool pages, reports and printed sheets across the 1,993 scenarios in both tiers, and fails on the 3.7.3 build; the 1,993 scenarios were re-run in both tiers with no difference; no size, count or factor changed; verified live after upload. 10/09/2026 (3.7.3): the rating record now states that soil thermal resistivity is not applied, the BS 7671 Appendix 4 buried ratings being tabulated at 2.5 K.m/W, and names Table 4B3 as the source of the factors for other resistivities; a service-size run of 35 mm2 or below sharing a trench with a larger cable prints a mixed-trench note explaining that the larger cable's spacing floor applies to the whole trench. Automated checks were added for both lines and fail on the 3.7.2 build; the 1,993 scenarios were re-run in both tiers with no difference; no size, count or factor changed; verified live after upload. 10/09/2026 (3.7.2): a check across every PD tool for a question asked of every user that only a minority case needs. The page-level default duct size control was found to apply only on a private route, where the size select on each duct and the private-route minimum already set the size, and its wording described a starting size for new ducts that the tool never used. It is removed; a private run still prints the minimum it applies and why. The 1,993 scenarios were re-run on 3.7.2 in both tiers with no difference, and an automated check now confirms that the control is absent and the private-route minimum still prints; no size, count or factor changed; verified live after upload. 04/09/2026 (3.7.1): a check of whether every input the standard names by a term of art is defined in the tool. The depth of lay, the clear spacing, the spare capacity and the duct catalogue, which holds the internal diameter and the outside diameter of every duct, all name their term. The manual size list did not: it now prints the internal diameter on every option, as the catalogue and the result already did. The 1,993 scenarios were re-run on 3.7.1 with no difference; no size, count or factor changed; verified live after upload. 04/09/2026: the full input range was enumerated, 1,993 scenarios in each tier, generated from the same independent replica: every multicore SWA size on every authority at three spare percentages, singly and in bundles, at two and three cables per duct; every single-core AWA size in flat, trefoil and quad formation; multicore and CPC pairs; concentric and Waveform cables; data and fire-performance cables in bundles up to 48; 11 kV and 33 kV on every DNO and IDNO; every standard duct size entered manually; mixed bundles; and spare capacity from 0 to 100%. Each case was driven through the tool's own interface and the printed duct size, working and spare duct counts, total, fill percentage, over-capacity state and circuits per duct were compared with the replica. No difference was found. 03/09/2026 (3.7.0): a check across every PD tool that every printed value is reached through the input the standard derives it from. The grouping factor was found to count cores rather than circuits, so a trefoil of three single-core cables read as three circuits; each cable line now states the cores forming one circuit and the record prints the derivation, with Table 4C3 named as an approximation where it is applied to a single-core set. Blank spare, spacing and depth ask for the value instead of sizing at a default; a small-power private run is no longer floored at 100 mm; the pulling stress is cited to BS EN 50565-1 and the unsourced aluminium figure is removed; the bending radius and clearance notes state their sources; the voltage is a visible choice; a mixed trench checks each authority's cover minimum. The 122 replica scenarios were re-run and all passed, with 20 small-power private cases returning the smaller duct now allowed; verified live after upload. 02/09/2026 (3.6.2): every cited clause was read back against BS 7671:2018+A4:2026; the single-core bonding note now cites Reg 523.201 (the earlier Reg 524.201 was a wrong clause number); the 122 scenarios were re-run and all passed; no size, count or factor changed. The sizing was validated on 122 scenarios (25/07/2026) against an independent replica of the sizing engine that reads the served configuration and the shared cable data rather than a copy of them: every SWA size as a single cable on a private route and on UK Power Networks, all six DNOs and an IDNO, mixed SWA and CPC pairs, bundles of 2 to 20, single-core sets in flat, trefoil and quad, concentric and Waveform cables, manual sizes including undersize, 2, 3, 4 and 6 cables per duct, spare capacity at 0, 10, 25 and 50%, service band and 11 kV and 33 kV minimums, and data cables. Every case is also checked against rules taken from the PD underground duct selection guide: working ducts never exceed the number of cables, one cable gives one working duct on every authority at every spare percentage, the internal diameter is at least 1.5 times the overall diameter and at least the authority minimum, the next standard size down must fail (the snug rule), spare ducts are the working count times the spare percentage rounded up with a DNO minimum of one, and a private route never totals more than the UK Power Networks equivalent. Thirteen further cases are hand calculated. All 122 were then driven through the tool's own interface with no difference in duct size, duct count, spare or fill. Grouping is verified against BS 7671 Table 4C3. The 122 replica scenarios were re-run on 12/08/2026 after the interface update and all passed. They were re-run again on 02/09/2026 after the 3.6.1 wording revision and all 122 passed; no size, count or factor changed.