# National Electric MFG National Electric MFG is a static public website offering UK-oriented electrical calculation aids, site planning flows and AI triage tools for temporary heaters, drying equipment, dehumidifiers, industrial fans, portable air conditioners, generators, RCDs, 110V transformers and site distribution. Canonical site: [https://www.nationalelectricmfg.com/](https://www.nationalelectricmfg.com/) ## Important boundaries - The site is a planning and triage aid, not electrical certification, design sign-off or competent-person replacement. - Users should verify calculations against current BS 7671 guidance, manufacturer data, site conditions and competent electrical judgement. - Tools avoid collecting personal data and run client-side where possible. ## Main indexes - [National Electric MFG | Temporary HVAC electrical calculators](https://www.nationalelectricmfg.com/) — UK electrical calculators and AI site tools for temporary heaters, dehumidifiers, air movers, portable AC, generators, RCDs, 110V transformers and site distribution. - [All electrical calculators and AI tools](https://www.nationalelectricmfg.com/tools/) — Browse all temporary HVAC electrical calculators, electrician tools and AI site tools on National Electric MFG. - [Temporary HVAC electrical calculators](https://www.nationalelectricmfg.com/temporary-hvac-electrical-calculators/) — Electrical calculation aids for temporary heaters, dehumidifiers, air movers, portable AC, 110V transformers, generators, RCDs and temporary distribution. - [UK electrician calculators and AI site tools](https://www.nationalelectricmfg.com/electrician-tools/) — BS 7671-aware UK electrician calculation aids for voltage drop, cable size, maximum demand, Zs, R1+R2, circuit schedules, EICR wording and temporary HVAC power. - [AI electrical site tools](https://www.nationalelectricmfg.com/ai-electrical-tools/) — AI photo, panel, nameplate, visual heat-risk and report drafting tools for temporary HVAC electrical planning. - [Temporary HVAC electrical super flows](https://www.nationalelectricmfg.com/flows/) — Connected workflows that combine several electrician calculators and AI tools for temporary heating, drying, cooling, RCD trip diagnosis and site power. ## Calculator and checklist tools - [110V transformer heater check](https://www.nationalelectricmfg.com/tools/110v-site-transformer-heater-feasibility-calculator/) — Check whether a 110V site transformer can realistically power temporary heaters, dehumidifiers, fans or drying kit without overload or ugly voltage drop. - [ACH fan calculator](https://www.nationalelectricmfg.com/tools/air-changes-per-hour-fan-calculator/) — Estimate airflow required for workshops, drying rooms, stores and warehouses by room volume and target air changes. - [Air mover placement](https://www.nationalelectricmfg.com/tools/air-mover-placement-planner/) — Suggest count and placement pattern for air movers in a drying room based on wet surface area and room shape. - [HVAC voltage drop envelope](https://www.nationalelectricmfg.com/tools/bs7671-voltage-drop-envelope-temporary-hvac/) — Estimate voltage drop over long leads for heaters, air movers, dehumidifiers and portable AC, with compressor start warnings. - [Cable correction factors](https://www.nationalelectricmfg.com/tools/cable-correction-factor-calculator-bs7671/) — Stack ambient temperature, grouping, insulation and installation correction factors to see whether corrected Iz still covers load current. - [Cable size + voltage drop](https://www.nationalelectricmfg.com/tools/cable-size-voltage-drop-calculator/) — High-demand UK cable and voltage-drop calculator reframed for temporary heaters, fans, dehumidifiers and portable AC. - [Connector selector](https://www.nationalelectricmfg.com/tools/commando-plug-connector-selector/) — Select a likely temporary connection class based on load current, voltage, environment and duty cycle. - [Condensate pump head](https://www.nationalelectricmfg.com/tools/condensate-pump-head-calculator/) — Check whether a dehumidifier or portable AC condensate route is likely to need a pump or a shorter drain path. - [CPC adiabatic](https://www.nationalelectricmfg.com/tools/cpc-adiabatic-equation-calculator/) — Use the adiabatic equation shape to compare fault current, disconnection time, k factor and CPC size as a planning aid. - [DB/test sheet checker](https://www.nationalelectricmfg.com/tools/db-circuit-schedule-test-sheet-checker/) — Paste circuit and test-sheet notes to flag missing Zs, R1+R2, IR, RCD or breaker details and generate a cleaner copyable schedule. - [Dehumidifier litres/day](https://www.nationalelectricmfg.com/tools/dehumidifier-size-litres-per-day-calculator/) — Estimate litres/day capacity from room volume, temperature, humidity and drying target, then check power requirements. - [Destratification savings](https://www.nationalelectricmfg.com/tools/destratification-fan-savings-calculator/) — Estimate whether destratification fans could reduce heat stacking and improve heater effectiveness in high spaces. - [Dew point risk](https://www.nationalelectricmfg.com/tools/dew-point-condensation-risk-calculator/) — Calculate dew point and cold-surface condensation risk, then decide whether heat, dehumidification or airflow is the first lever. - [Drying room power plan](https://www.nationalelectricmfg.com/tools/drying-room-power-plan-calculator/) — Combine dehumidifiers, air movers and support heaters into a staged circuit plan for drying jobs. - [Ducting fan derate](https://www.nationalelectricmfg.com/tools/ducting-static-pressure-derate-calculator/) — Estimate how duct length, bends, inlet restrictions and outlet restrictions reduce nominal fan airflow. - [EICR observation coder](https://www.nationalelectricmfg.com/tools/eicr-observation-coder/) — Draft C1/C2/C3/FI-style wording for common observations around overloaded sockets, damaged reels, RCD issues and temporary HVAC equipment. - [Heater amps](https://www.nationalelectricmfg.com/tools/electric-heater-amps-calculator/) — Convert heater kW into current at 110V, 230V or 400V and check 13A, 16A, 32A and three-phase supply classes. - [Heater supply selector](https://www.nationalelectricmfg.com/tools/electric-heater-supply-selector/) — Pick the likely connection class for an electric heater: 13A plug, 16A, 32A, 63A or three-phase. - [Lead/PAT visual checklist](https://www.nationalelectricmfg.com/tools/extension-lead-pat-visual-checklist/) — A practical visual checklist for plugs, sockets, reels, commando connectors and temporary HVAC leads before use. - [Generator kVA + start current](https://www.nationalelectricmfg.com/tools/generator-kva-compressor-start-calculator/) — Size a generator for portable AC, dehumidifiers, fans and heaters with a start-current allowance rather than only running watts. - [Heater cable reel derating](https://www.nationalelectricmfg.com/tools/heater-cable-reel-derating-calculator/) — Check whether a coiled, partly unwound or long extension reel is a bad match for a 2kW or 3kW temporary heater. - [Heater staging sequencer](https://www.nationalelectricmfg.com/tools/heater-staging-phase-sequencer/) — Plan staged heater switching and phase allocation so large temporary heating sets do not hit one supply at once. - [IR test triage](https://www.nationalelectricmfg.com/tools/insulation-resistance-test-triage/) — Turn L-N, L-E and N-E insulation-resistance readings into practical next-step notes for damp circuits, appliances and fault finding. - [Max demand + diversity](https://www.nationalelectricmfg.com/tools/max-demand-diversity-calculator-temporary-hvac/) — Estimate realistic demand where heaters, compressors, fans and drying equipment do not all peak together. - [Max Zs checker](https://www.nationalelectricmfg.com/tools/max-zs-checker-mcb-rcbo-bs7671/) — Check a measured Zs value against an entered device limit, with optional 80% rule headroom and clear pass/check wording. - [MCB curve / motor start](https://www.nationalelectricmfg.com/tools/mcb-curve-motor-start-calculator/) — Estimate whether fan or compressor starting current is likely to be harsh for a B, C or D curve MCB. - [Drying log builder](https://www.nationalelectricmfg.com/tools/moisture-reading-drying-log-builder/) — Create a simple daily drying log with RH, temperature, moisture readings, equipment and circuit notes. - [Negative pressure / scrubber](https://www.nationalelectricmfg.com/tools/negative-pressure-air-scrubber-calculator/) — Estimate air scrubber airflow needed to maintain containment or repeated air cleaning in a work zone. - [Panel schedule builder](https://www.nationalelectricmfg.com/tools/panel-circuit-schedule-builder/) — Create a printable schedule for boards feeding temporary heaters, dehumidifiers, fans, drying kit or AC. - [Portable AC BTU/kW](https://www.nationalelectricmfg.com/tools/portable-ac-btu-kw-calculator/) — Estimate portable AC capacity in kW and BTU/h for offices, plant rooms, events, kitchens and workshops. - [AC condensate plan](https://www.nationalelectricmfg.com/tools/portable-ac-condensate-plan-calculator/) — Plan tank emptying, gravity drain or pump route for unattended portable AC operation. - [AC exhaust derate](https://www.nationalelectricmfg.com/tools/portable-ac-exhaust-duct-derate-calculator/) — Estimate cooling performance loss from long exhaust duct runs, bends and recirculation risk. - [Spot cooling load](https://www.nationalelectricmfg.com/tools/portable-ac-spot-cooling-load-calculator/) — Estimate spot cooling for server rooms, production lines, events and overheated work zones. - [AC start current](https://www.nationalelectricmfg.com/tools/portable-ac-start-current-calculator/) — Estimate start-current pressure on breakers or generators for portable AC and compressor loads. - [PFC / fault current](https://www.nationalelectricmfg.com/tools/prospective-fault-current-calculator-uk/) — Estimate PSCC or PEFC from Ze and voltage, compare against device breaking capacity, and draft a quick test-sheet note. - [RCD leakage budget](https://www.nationalelectricmfg.com/tools/rcd-leakage-budget-nuisance-trip-calculator/) — Estimate cumulative leakage from compressors, dehumidifiers, portable AC, heaters, pumps and long wet leads before stacking everything behind one RCD. - [RCD trip time checker](https://www.nationalelectricmfg.com/tools/rcd-trip-time-checker/) — Review x0.5, x1 and x5 RCD trip-time readings and produce a clear pass/check prompt for the job file. - [RCD type selector](https://www.nationalelectricmfg.com/tools/rcd-type-selector-hvac-loads/) — A selector aid for AC, dehumidifiers, inverter drives, electronic controls and mixed temporary HVAC equipment. - [Refrigerant vs desiccant](https://www.nationalelectricmfg.com/tools/refrigerant-vs-desiccant-dehumidifier-selector/) — Choose a dehumidifier type based on temperature, RH, target and site conditions. - [Ring final load check](https://www.nationalelectricmfg.com/tools/ring-final-continuous-load-checker/) — Estimate continuous heater, dehumidifier and socket-load pressure on a ring final circuit, including spurs, adaptors and run-time warnings. - [Temporary DB planner](https://www.nationalelectricmfg.com/tools/temporary-distribution-board-planner/) — Lay out a temporary board for heaters, drying equipment, fans, portable AC and lighting, with circuit groups and notes. - [Three-phase load balancer](https://www.nationalelectricmfg.com/tools/three-phase-load-imbalance-optimizer/) — Allocate single-phase heaters, dehumidifiers, fans and portable AC units across L1/L2/L3 to reduce imbalance and nuisance trips. - [Ventilation heat loss](https://www.nationalelectricmfg.com/tools/ventilation-heat-loss-calculator/) — Estimate extra heat needed when extract fans, open doors or air changes are dragging warm air out of a workspace. - [Zs / R1+R2](https://www.nationalelectricmfg.com/tools/zs-r1-r2-calculator/) — Calculate expected Zs from Ze and R1+R2, or derive R1+R2 from measured Zs for circuit assessment notes. ## AI-assisted site tools - [AI plug/reel visual check](https://www.nationalelectricmfg.com/ai/cable-reel-plug-condition-checker/) — A photo-led checklist for coiled reels, discolouration, cracked plugs, loose strain relief and overloaded adaptors. - [EICR remedial scope](https://www.nationalelectricmfg.com/ai/eicr-remedial-scope-writer/) — Turn observations into a clear remedial scope, materials prompt and temporary equipment restriction note. - [AI nameplate reader](https://www.nationalelectricmfg.com/ai/equipment-nameplate-reader/) — Upload or type nameplate details from heaters, dehumidifiers, fans or AC units and extract voltage, current, watts, phase and IP hints. - [AI panel photo map](https://www.nationalelectricmfg.com/ai/panel-photo-circuit-map/) — Upload a board photo and create a draft circuit map, breaker list, RCD group notes and temporary HVAC suitability questions. - [Quote pack builder](https://www.nationalelectricmfg.com/ai/quote-pack-builder/) — Create a compact pack with assumptions, equipment list, circuit plan, risk flags and NHS category references. - [AI drying layout](https://www.nationalelectricmfg.com/ai/room-photo-drying-layout-planner/) — Use a room photo plus measurements to draft dehumidifier and air mover placement notes for drying jobs. - [Method statement generator](https://www.nationalelectricmfg.com/ai/temporary-hvac-method-statement-generator/) — Draft a method statement outline for temporary heating, drying, ventilation or cooling equipment on site. - [AI thermal-style risk scan](https://www.nationalelectricmfg.com/ai/thermal-visual-overheating-scanner/) — Use a normal phone photo for a thermal-style risk overlay based on visible clues, or upload true thermal imagery when available. ## Job-flow pages - [Flood Drying Electrical Plan](https://www.nationalelectricmfg.com/flows/flood-drying-electrical-plan/) — Turn room size, humidity and available power into a drying stack: dehumidifiers, air movers, heater support, RCD split and daily log. - [Generator-Powered Temporary HVAC Setup](https://www.nationalelectricmfg.com/flows/generator-powered-temporary-hvac-setup/) — Build a generator plan for heaters, AC, dehumidifiers and fans with kVA, compressor start, voltage drop, RCD and sequencing checks. - [Nuisance RCD Trip Diagnosis](https://www.nationalelectricmfg.com/flows/nuisance-rcd-trip-diagnosis/) — Diagnose why drying, cooling or heating equipment trips protection: leakage budget, start current, panel map, lead condition and visual heat-risk scan. - [Panel Photo to EICR/Remedial Scope](https://www.nationalelectricmfg.com/flows/panel-photo-to-eicr-remedial-scope/) — Use a board photo, circuit schedule, Zs/R1+R2 values and EICR wording helpers to draft a remedial scope and temporary equipment restrictions. - [Portable AC Event & Server-Room Power Plan](https://www.nationalelectricmfg.com/flows/portable-ac-event-server-room-power-plan/) — Estimate cooling, start current, exhaust duct losses, condensate handling and generator demand for temporary cooling. - [Site Heating Power Check](https://www.nationalelectricmfg.com/flows/site-heating-power-check/) — A guided flow for answering: can this site supply run the electric heaters without cooking reels, dropping voltage or overloading one phase? - [Warehouse Fan & Heater Balance](https://www.nationalelectricmfg.com/flows/warehouse-air-movement-heating-balance/) — Link high-bay heat loss, door ventilation, destratification and temporary electric heater power into one plan. ## Reference pages - [About National Electric MFG](https://www.nationalelectricmfg.com/about/) — National Electric MFG is a practical calculator and AI tooling site for competent persons planning temporary heating, drying, cooling, ventilation and - [Contact](https://www.nationalelectricmfg.com/contact/) — For corrections, tool suggestions or partnership enquiries, contact the site operator through the usual project channel. Do not send emergency electri - [Methodology](https://www.nationalelectricmfg.com/methodology/) — Calculations are planning aids using simplified electrical, psychrometric and airflow formulae. They intentionally include safety margins and amber/re - [Privacy](https://www.nationalelectricmfg.com/privacy/) — This static site does not require accounts. Browser-side calculators run locally. Uploaded image tools in this MVP operate locally in the browser for - [Terms](https://www.nationalelectricmfg.com/terms/) — Use these tools as educational and planning aids only. They do not replace electrical design, inspection, testing, risk assessment, manufacturer instr ## Machine-readable discovery - [Sitemap XML](https://www.nationalelectricmfg.com/sitemap.xml) - [Robots TXT](https://www.nationalelectricmfg.com/robots.txt) - [Open Graph image](https://www.nationalelectricmfg.com/og.svg)