Safety, hygiene and quality in installation work
A well-calculated installation can be ruined during assembly: a badly placed ladder, a terminal without the right tightening torque, a cable that is not what the label says. On site you are asked, besides knowing how to do the job, to do it without hurting anyone —safety and hygiene— and to do it in a way that lets you prove it is right —quality—.
The effects of current on the body, the five golden rules, arc flash and the general legal framework (Law 19,587, Decree 351/79) are in occupational health and safety. Which document is binding and what the certificate of suitable installation is, in regulations for electrical installations. Lockout and work permits for maintenance tasks, in maintenance management.
Here the subject is what shows up when you install: the hazards of the site, how they are analyzed and controlled, and how the quality of the work and of the materials is organized and verified.
01The hazards of installation work
In a workshop the main hazard is voltage. On a site, the hazards of any construction site are added: the electrician also falls, gets cut, lifts weight and works in enclosed places. This table gathers those that recur most when installing a system, and the measure that applies to each.
| Hazard | When it appears during installation | Main measures |
|---|---|---|
| Work at height | Conduits and trays in ceilings, luminaires, roofs, slab edges and uncovered openings. | Remove the height if possible (pre-assemble on the ground). Guardrails, nets and covers on openings. Without collective protection, a fall-arrest harness with a lifeline or suitable anchor. Never work alone. |
| Ladders | Short, light tasks: a box, a fixture, a branch connection. | Firm, level footing; the 4-to-1 rule (Figure 1); extend 1 m above the support; one person at a time; stepladder with the spreaders locked. Near live parts, a fiberglass or dry-wood ladder, never metal. |
| Scaffolds and platforms | Switchboards, trays and luminaires that take several hours of work at height. | Erected by trained personnel following the manufacturer’s manual. Level, braced bases; complete platforms with guardrails and toe boards; access by its own ladder; daily inspection before use. |
| Tools | Drill, hammer drill, powder-actuated tool, wire strippers, utility knife; corded power tools. | Tool in good condition, double insulated, with intact cord. Guards in place. Powered from a board with a residual current device. Powder-actuated tool only for authorized personnel. |
| Confined spaces | Splice chambers, pits, tanks, attics and hard-to-reach ducts. | Entry permit. Prior measurement of oxygen and gases. Ventilation. An attendant outside with communication and a rescue plan. |
| Arc flash | Commissioning, tests and switching on energized boards; wiring mistakes. | Do not energize until finished and verified. Energizing is a milestone with a permit and a clear area. Arc-rated clothing and face shield, with their cal/cm² rating. Causes and protection are in health and safety. |
| Cutting and grinding | Cutting trays, sections and ground rods; chasing walls to embed conduits. | Wheel suitable for the material and the machine’s speed, guard in place, work piece clamped, face shield, glasses, gloves. Sparks away from combustibles. When chasing, respirator and wetting: masonry dust damages the lungs. |
| Loads | Cable reels, boards, transformers, tray sections, bags. | Mechanize: trolley, hand truck, hoist. Move in pairs. Lift with the legs, not the back. Stack stably. Ergonomic criteria are in SRT Resolution 295/2003. |
For construction sites Decree 911/96 also applies, the occupational health and safety regulation for the construction industry, which brings Law 19,587 down to site work and includes requirements for scaffolds, ladders and fall protection. It is the document to consult when there is a doubt about how site equipment is erected or used.
You have to climb to the edge of a slab that is 3.00 m above the floor. The foot distance is a quarter of the height of the support:
The ladder reaches the support along the hypotenuse of the triangle:
Since it must extend 1 m to step onto the slab, you need a ladder at least 3.09 m + 1.00 m = 4.09 m long. And the resulting angle:
Check by another route: b/L = 0.75 / 3.09 = 0.2425, which is the cosine of 75.96°. It matches.
An almost vertical ladder tips backwards when the climber leans. A very flat one slides at the foot or bends. The 4-to-1 rule is the middle ground. It is checked with a tape before climbing, not by eye.
Most victims in these places are the second and third people who go in to help the first. If someone collapses inside, the attendant raises the alarm and activates the rescue plan: does not enter. Only rescue personnel with self-contained breathing apparatus and a rope go in.
02Protection, signage, order and cleanliness
The order of measures is the one seen in health and safety: eliminate the hazard, substitute it, protect everyone with collective measures, signpost and organize the work, and only at the end protect one person with their personal protective equipment (PPE). On a site that means, for example, a guardrail before a harness, and a sheath covering the cable before a glove.
Protects everyone who passes, without relying on each person doing something: guardrails and nets, covers on openings, fences and tape closing off an area, site boards with a residual current device, temporary lighting, lifelines, machine guards, forced ventilation.
Protects one person, and only if properly chosen, properly worn and in good condition. The employer supplies it at no cost, certified and with a delivery record (SRT Resolution 299/2011); the worker uses it and reports when it deteriorates.
| Item | When it is used during installation | To keep in mind |
|---|---|---|
| Hard hat | Everywhere on site, especially when working below others. | For electrical tasks, with no metal parts. Replace it after a hard blow even if nothing shows. |
| Safety glasses and face shield | Drilling, grinding, cutting, head up under a ceiling; face shield for arc. | Ordinary glasses do not replace safety glasses. |
| Gloves | Leather or cut-resistant for handling; insulating gloves for live work. | Insulating gloves are inspected and air-tested for leaks before every use and tested periodically. |
| Safety footwear | Always. With an insulating sole for electrical tasks. | With toe cap. Sports shoes are not site footwear. |
| Harness and lanyard | Work at height without collective protection. | You need an anchor and must calculate the clear fall height: a wrongly chosen lanyard does not stop the fall in time. |
| Hearing protection | Hammer drill, grinder, compressor. | From 85 dB(A) sustained. |
| Respirator | Chasing, drilling masonry, dusty environments. | The filter must match the contaminant. |
| Work clothing | Always. Cotton or flame-resistant when there is an arc hazard. | Never synthetic in electrical tasks: it melts onto the skin. |
Site signage
Signs are understood without reading because they always use the same color and shape. The colors and safety signs are set by the standard IRAM 10005. On site they are complemented with tape, fences and area notices:
| Color | Meaning | Examples on an electrical site |
|---|---|---|
| Red | Prohibition and fire-fighting equipment. | “Do not energize” next to a lockout; fire extinguishers; “no entry”. |
| Yellow | Warning of a hazard. | “Electrical hazard” on boards and chambers; “slippery floor”; “suspended loads”. |
| Blue | Mandatory action. | “Hard hat required”, hearing protection or harness required. |
| Green | Rescue and safe condition. | Emergency exit, first-aid kit, emergency shower, assembly point. |
The status of equipment is also signposted: the lockout tag, the “equipment under repair” notice and the label of each breaker on the board. A sign that is not where it is needed, or that stayed up after the hazard is gone, teaches people to ignore signs.
Order and cleanliness
It is the cheapest measure and the one most often skipped. A cable offcut on the floor is a fall; a cardboard box next to the board is a fire source; a corridor taken up by materials is a blocked exit. A simple method is the 5S, which was born in quality management:
| S | What you do | At the installation workstation |
|---|---|---|
| 1 | Sort | Remove what is not needed for the day’s task. |
| 2 | Set in order | Everything has its place: tools in the bag, materials stacked and labeled, corridors clear. |
| 3 | Shine | Sweep offcuts and dust before leaving; waste goes to its container (copper is recycled). |
| 4 | Standardize | Everyone does the same: same place for the extinguisher, same labeling, same rules. |
| 5 | Sustain | Checked with a short round, and any deviation corrected the same day. |
03Safety plan and risk analysis of a task
The site safety plan
Before the site opens, how the work will be done safely is written down. On a construction site the employer draws up a safety program and notifies the site to its ART (workers’ compensation insurer), under Decree 911/96 and SRT Resolution 51/97; beyond a certain size a licensed health and safety professional takes part. The requirements by type and size of site are looked up in the current regulation. The usual contents are:
| Section | What it contains |
|---|---|
| Data and scope | What the site is, its stages, how many people, which companies take part. |
| Responsibilities | Who directs, who monitors safety, who gives the order to energize. Names, not generic job titles. |
| Risk analysis by stage | The hazards of each task and their measures (see below). |
| Safe procedures | In writing: lockout and verification, work at height, confined spaces, lifting loads, energizing. |
| PPE and training | What is issued to each position, with a record of delivery and of the talks given. |
| Temporary installations and signage | Site board with protections, lighting, fences, notices, order and cleanliness. |
| Emergency plan | Evacuation, first aid, phone numbers, assembly point, who calls emergency services. |
| Monitoring | Periodic inspections, record of incidents and unsafe conditions, audits. |
Analysis of a task
The plan is general; the job safety analysis (JSA) goes down to a specific task and is done before starting it, with the people who will do it. It always follows the same path:
- Break the task into steps.
- Identify the hazard in each step: what can go wrong and whom it would hurt.
- Assess the risk: how likely it is and how severe it would be.
- Define measures, in order of effectiveness: eliminate, substitute, protect collectively, procedures and signs, PPE.
- Assess again with the measures in place and check that the remaining risk is acceptable.
- Communicate to the whole team, sign, and review if anything changes on site.
Risk is assessed by multiplying a probability scale by a severity scale:
In this topic’s example both run from 1 to 5, and the result is classified into four levels: low (1 to 4), moderate (5 to 9), high (10 to 15) and critical (16 to 25). Each company defines its own scale; what matters is that it is always the same and that it is written down.
This is the full analysis of one task: running conduit and cable through the ceiling of a room at 2.8 m height with a stepladder, in an area that has an existing installation.
| Hazard | P | S | R | Measures | P | S | R |
|---|---|---|---|---|---|---|---|
| Fall from the ladder | 4 | 4 | 16 critical | Stepladder with spreaders locked, level base, a coworker holds it; low platform instead of a ladder if the task is long. | 2 | 4 | 8 moderate |
| Contact with energized conductors in the ceiling | 3 | 5 | 15 high | Cut off the area, lock out and verify absence of voltage (the five rules); non-metallic ladder. | 1 | 5 | 5 moderate |
| Cut by the grinder when cutting the conduit | 3 | 3 | 9 moderate | Replace the grinder with a conduit cutter or a hand saw: the wheel is eliminated. | 1 | 2 | 2 low |
| A tool falling on someone | 3 | 3 | 9 moderate | Tape closing off the area below, tool in a bag with a lanyard, hard hat for anyone passing. | 1 | 3 | 3 low |
The multiplications: 4 · 4 = 16; 2 · 4 = 8; 3 · 5 = 15; 1 · 5 = 5; 3 · 3 = 9; 1 · 2 = 2; 3 · 3 = 9; 1 · 3 = 3. Electrical contact, even with the measures, stays at 5: the severity does not drop, because if it happened it would be just as serious; the only thing that can be reduced is the probability, which is why that measure is the strictest of all.
A JSA filled in after the work is paperwork. A JSA discussed for five minutes beforehand, with the team standing in front of the place, finds what the desk did not see: the wet floor, the other crew working above, the board someone labeled wrongly.
If after the measures the risk is still high or critical, the task does not start: more measures are added or the method is changed. That everyone signed the analysis does not reduce the probability or the severity of anything.
04Quality and its standards
Quality is meeting the requirements: those in the drawing and the specification, those imposed by the regulation (AEA 90364) and those the client takes for granted, such as the installation lasting. On an electrical site two different qualities coexist and are controlled differently: that of the materials that arrive and that of the work with which they are installed.
| Type of standard | What it says | Examples |
|---|---|---|
| Product | How a material must be and how it is tested. | IRAM-NM 247-3 (PVC-insulated cables), IRAM-NM 60898 (circuit breakers for household installations). |
| Installation | How it is designed, installed and verified. | AEA 90364 (see regulations). |
| Quality management | How a company organizes its work to meet the requirements always, not by chance. | ISO 9001 (in Argentina, IRAM-ISO 9001). |
| Safety management | How a company organizes the prevention of occupational risks. | ISO 45001. |
ISO 9001: quality management
ISO 9001 does not say what a cable or a board must be like. It says how an organization must work so that what it delivers meets what it promised. It rests on two ideas:
Work is seen as processes: something comes in (drawings, materials, people), is transformed with resources and controls, and a result comes out (the finished installation). In each process, who is responsible, what is controlled and by what criterion are defined. Quality is built into the process; the final check comes too late.
Plan, do, check and act, over and over. Each turn learns from the previous one: what happened is measured, it is corrected and the plan is adjusted. The standard calls this continual improvement.
The standard also has seven principles (customer focus, leadership, engagement of people, process approach, improvement, evidence-based decision making and relationship management with suppliers) and asks for concrete things: documenting procedures, keeping records, running internal audits, handling nonconformities and correcting their causes.
The organization is certified: that it manages its processes. It does not say that each installation it builds complies with AEA 90364, or that each material is safe. A certified company can make mistakes; the difference is that it has a system to detect and correct them.
Product quality: certification and safety mark
Low-voltage electrical materials sold to the public in Argentina fall under an electrical product safety regime issued by the Secretaría de Comercio: the manufacturer or importer must show, with a certificate from a recognized certification body, that the product meets the applicable safety standard, and then identifies it with the electrical safety mark. IRAM is one of the bodies that writes standards and also certifies. The current resolution and the products covered are looked up on the official site, because they change.
Visible, legible marking (manufacturer, standard, rated voltage and current, cross-section for a cable), safety mark or batch certificate, datasheet, intact packaging, and that it is what the specification asks for and what the project schedule lists. A price far below market is a warning sign, not a bargain.
A 100 m reel of cable labeled “2.5 mm²” arrives. With a four-wire ohmmeter, one conductor is measured end to end: 1.15 Ω. The resistance it should have, with ρ = 0.0175 Ω·mm²/m:
The conductor standard (IRAM-NM 280, equivalent to IEC 60228) allows at most 7.98 Ω/km at 20 °C for a stranded 2.5 mm² conductor, that is, 0.798 Ω in 100 m. The 1.15 Ω exceeds it. The real cross-section comes from the same formula:
Check by another route: 1.15 / 0.700 = 1.64 times the expected resistance, so the cross-section is 2.5 / 1.64 = 1.52 mm². It is a 1.5 mm² cable labeled as 2.5 mm²: the batch is rejected and recorded as a supplier nonconformity.
05Quality control on site
To inspect is to compare what was done against a criterion fixed beforehand. It is done at three moments, and the sooner a defect is detected, the less it costs to fix: replacing a cable before pulling it takes minutes; replacing it after pouring and plastering is a demolition.
| Inspection | When | What is checked in an installation |
|---|---|---|
| Receiving | When the material arrives. | Marking, mark, real cross-section, match with the specification (see the cable example). |
| In process | During installation, before covering. | Conduits, bends and fixings; number of conductors per conduit; splices; earthing. What will later be hidden is checked beforehand. |
| Final | Before energizing and handing over. | Labeling, terminal tightness, continuity, insulation and residual current devices, with instruments. It feeds the certificate of suitable installation. |
What is inspected and when is defined in an inspection point plan. Some points are hold points: the work does not continue until the inspector has approved them. A typical case is whatever will be covered. The result of each inspection is recorded in a protocol: a form with the item, the acceptance criterion, the measured value, the result (conforming or nonconforming), the date and the signature. This is the one for a sub-board already installed, TS2:
| Item | Acceptance criterion | Measured result | Status |
|---|---|---|---|
| Labeling of circuits and board | All labeled as in the drawing | 12 of 12 | Conforming |
| Conductor colors | Neutral light blue, protective green-yellow | Correct | Conforming |
| Terminal tightness | Datasheet torque, with a torque wrench | 35 of 40 at torque; 5 below | Nonconforming |
| Continuity of the protective conductor | Measured at each socket | 12 of 12 | Conforming |
| RCD at IΔn | Trips in 300 ms or less | 62 ms | Conforming |
Nonconformities and corrective actions
A nonconformity is a requirement that was not met. Detecting it is not a fault: it is the system working. What is a fault is hiding it or fixing it silently, because then it happens again.
The correction fixes this defect: re-tightening the loose terminal. The corrective action eliminates the cause, so that it does not recur: why it was loose, and what changes in the method so that no terminal is loose in any board. If you only correct, the defect reappears in the next board. ISO 9001 requires both (clauses 8.7 and 10.2).
The path is always the same: detect, record, contain, find the cause, apply the corrective action, verify that it worked and close. This is how the terminal-tightness one in board TS2 was resolved:
| Field | Record |
|---|---|
| No. and classification | NC 007 · major (a loose terminal heats up and can start a fire). |
| Description and evidence | In TS2, 5 of 40 terminals with a torque below the datasheet value, measured with a torque wrench. Photos and protocol. |
| Immediate correction | Re-tighten all 40 terminals of TS2 to the specified torque and mark each with control paint. |
| Containment | Check the other 5 sub-boards (200 terminals): 11 below torque. In total, 16 of 240 terminals. |
| Root cause (5 whys) | Why were they loose? They were tightened by hand with a screwdriver. Why? There was no torque wrench in the kit. Why? The procedure said “tighten fully”, with no value. Why? The inspection point plan had no torque check. Why? The protocol template did not include that item. |
| Corrective action | Torque screwdriver in every kit; the torque value in the procedure; the item “tightening torque” as an inspection point with paint mark; team training. Responsible: installation supervisor. Deadline: 5 days. |
| Effectiveness check | In the next 3 boards (120 terminals): 0 below torque. |
| Closure | Signed by the site manager. The protocol template is updated for future jobs. |
The defect rates, twice: TS2, 5 / 40 = 0.125, that is 12.5 %. Total checked, 16 / 240 = 0.0667, that is 6.7 % (check: 5 + 11 = 16 terminals, 40 + 200 = 240).
The contact resistance of a loose terminal is much higher than that of a tight one, and the power dissipated grows with it and with the square of the current. The heat softens the insulation and loosens the contact even more. That is why this nonconformity is major and why it is checked with an instrument (the thermography of maintenance of electrical components finds the ones that slipped through).
The signed protocols, the closed nonconformities and the measurements make up the site file. From it comes the certificate of suitable installation (see regulations) and from it starts the maintenance history discussed in maintenance management.
06On site
In groups, choose an installation task that can be done in the workshop: installing a light box in a ceiling with a stepladder. Break it into steps, list the hazards, assess P · S with the scale of this topic, propose measures in order of effectiveness and assess again. Acceptance criterion: no residual risk high or critical, and every measure has a person responsible. Present it to the rest as a five-minute talk.
Materials: single ladder, tape measure, square, a mark on the wall at 2.40 m. Calculate beforehand the foot distance and the length up to the support, place the ladder, measure and record. Acceptance criterion: foot at 0.60 m ± 5 cm from the wall, firm support, 1 m extension, and a coworker holding it. Then place it badly on purpose (at 0.30 m and at 1.20 m) and discuss how it looks and feels.
Materials: a 100 m reel of 2.5 mm² cable, a four-wire ohmmeter (or a milliohmmeter) and calipers. Steps: read and note the marking, measure the conductor diameter, measure the resistance of one conductor end to end, calculate the real cross-section. Acceptance criterion: complete marking and a resistance of 0.798 Ω or less at 20 °C. Fill in a receiving protocol and, if it fails, open a nonconformity.
One group builds a training board with three hidden defects (a loose terminal, a wrongly labeled conductor, an unconnected earth). The other inspects it with a protocol, without knowing which ones. Each defect found is recorded as a nonconformity, with its cause and corrective action. Acceptance criterion: all three detected, and the corrective action attacks the cause and not just the symptom. Then they swap roles.
07Common mistakes
| Mistake | Consequence |
|---|---|
| Leaning the ladder “however it fits” or climbing with hands full | A fall from a low height can be serious. The 4-to-1 rule and two free hands cost nothing. |
| Using a metal ladder near live parts | The ladder conducts: accidental contact goes through the body. |
| Grinding without a guard or with a worn wheel | Flying fragments and serious cuts; a broken wheel leaves at high speed. |
| Going into a pit “just for a moment” | An oxygen-poor atmosphere gives no warning. It is measured beforehand and an attendant stays outside. |
| Making PPE the only defense | It protects one person and only if used properly. First comes the hazard eliminated or guarded for everyone. |
| Filling in the job safety analysis after the work | It is a useless paper: it did not discover any hazard when it could be useful. |
| Believing that “ISO 9001 certified” means “product approved” | The standard certifies the organization; the material is verified with its product standard and by testing. |
| Fixing the defect without looking for the cause | This terminal is fixed and the same ones show up in the next board. |
| Signing the protocol without measuring | It is a false record. If there is an accident, whoever signed is held to account. |
| Trusting the cable label | There are reels with less copper than labeled: resistance and diameter are checked. |
08Self-assessment
Why does PPE come last in the order of measures?
Because it protects one person, and only if properly chosen, properly worn and in good condition. Before it come eliminating the hazard, substituting it and protecting everyone with collective measures, which do not depend on each person’s behavior.
A ladder must lean on a point at 2.40 m height. How far from the wall does the foot go, and how long must the ladder be up to the support?
With the 4-to-1 rule:
Check: 0.60 / 2.47 = 0.243, the cosine of 76°, the slope given by the rule. If it must extend 1 m, the ladder is at least 3.47 m long.
A hazard has probability 3 and severity 5. What risk level is it and what is the first measure?
R = 3 · 5 = 15, level high. The first measure is the most effective one: eliminate the hazard, that is, work de-energized (lockout and verification). With that the probability drops to 1 and the risk to 1 · 5 = 5, moderate; the severity does not change.
What does ISO 9001 certify: the company or its products?
The organization: that it manages its processes to meet requirements and improve. It does not guarantee that each product or installation meets its technical standard; that is verified with the product standard, AEA 90364 and testing.
A 100 m reel labeled 2.5 mm² reads 0.93 Ω end to end. What cross-section does it have and what is done?
Real cross-section:
Check: the expected resistance is 0.700 Ω; 0.93 / 0.700 = 1.33 and 2.5 / 1.33 = 1.88 mm². It also exceeds the 0.798 Ω maximum. It does not comply: the batch is rejected and a nonconformity is opened with the supplier.
In which stage of PDCA is the inspection protocol done, and what happens to what is found?
In Check (clause 9). What is found and does not comply is recorded as a nonconformity and goes to Act (clause 10): correction, search for the cause, corrective action and update of the plan.
In a board, 3 of 25 terminals are below torque. What defect rate is that, and what is done besides re-tightening those 3?
Rate:
Besides the correction you must contain (check the rest of the boards) and find the cause for a corrective action: the tool, procedure or inspection that failed. Then you verify that it worked.