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O telefone toca: “metade da casa apagou”, “o GFCI não rearma”, “a tomada está quente”. Para o eletricista que atende residência nos Estados Unidos, o dia é feito desses chamados. Este guia grátis junta os vinte mais comuns num lugar só: o que costuma ser, o que medir primeiro, o conserto de sempre, quanto tempo leva e quanto se cobra.
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Guia dos 20 chamados do eletricista: o que medir, conserto, tempo e preço, em inglês
O guia está em inglês e tem onze páginas. Aqui você vê o método de cinco passos, as leituras normais do multímetro e a lista dos vinte chamados com tempo e preço. O PDF para baixar fica no topo da página seguinte.
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Por que chamado de serviço dá dinheiro
Obra nova depende de projeto, licença e cronograma. O chamado de serviço é diferente: o cliente tem um problema hoje, quer resolver hoje e paga a visita. Quem acha o defeito rápido fecha mais chamados por dia, e quem explica bem o que achou ganha o cliente para o próximo serviço. O segredo é sempre seguir a mesma ordem, em vez de sair abrindo caixa por caixa.
O método de cinco passos
Vale para os vinte chamados. Os dois primeiros passos resolvem uma boa parte deles sem ferramenta nenhuma, porque muita tomada morta é só um GFCI desarmado em outro cômodo.
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| Passo | O que fazer |
|---|---|
| 1. PERGUNTAR | Quando começou? O que estava ligado? Teve obra, tempestade ou aparelho novo? |
| 2. OLHAR | Quadro, todos os GFCI, marcas de queimado, cheiro, água. Muitos chamados terminam aqui. |
| 3. MEDIR | Vivo-morto-vivo: teste o multímetro numa fonte boa, meça, teste de novo na fonte boa. |
| 4. ISOLAR | Tire as cargas, abra o circuito no meio, desligue o LOAD. |
| 5. CONSERTAR E PROVAR | Conserte, meça de novo, mostre ao cliente e anote na ficha. |
| Step | What to do |
|---|---|
| 1. ASK | When did it start? What was running? Any recent work, storm or new appliance? |
| 2. LOOK | Panel, every GFCI, scorch marks, smell, water. Most calls end here. |
| 3. MEASURE | Live-dead-live: test the meter on a known source, test, test again. |
| 4. ISOLATE | Unplug loads, open the circuit at a midpoint, disconnect LOAD. |
| 5. FIX + PROVE | Repair, retest with the meter, show the client, write it on the ticket. |
| Step | What to do |
|---|---|
| 1. ASK | When did it start? What was running? Any recent work, storm or new appliance? |
| 2. LOOK | Panel, every GFCI, scorch marks, smell, water. Most calls end here. |
| 3. MEASURE | Live-dead-live: test the meter on a known source, test, test again. |
| 4. ISOLATE | Unplug loads, open the circuit at a midpoint, disconnect LOAD. |
| 5. FIX + PROVE | Repair, retest with the meter, show the client, write it on the ticket. |
Vivo-morto-vivo, sempre
O detector de tensão sem contato ajuda a achar o circuito, mas sozinho não prova que o fio está desligado. Teste o multímetro numa fonte que você sabe que está ligada, meça o ponto em que vai trabalhar e volte a testar na fonte boa. Se o aparelho falhou no meio do caminho, você descobre antes de encostar no fio.
Como é uma leitura normal
Antes de abrir qualquer coisa, compare o que o multímetro mostra com estes valores de uma casa americana típica. Leitura fora da faixa é a primeira pista.
| Teste | Normal | Observação |
|---|---|---|
| Tomada 120 V, fase-neutro | 114 – 126 V | Faixa A da ANSI C84.1 para 120 V |
| Fase-terra | igual à fase-neutro | Perto de 0 V = sem terra |
| Neutro-terra | abaixo de 2 V | Mais que isso com carga = neutro frouxo ou longo |
| 240 V, L1-L2 | 228 – 252 V | Faixa A da ANSI C84.1 para 240 V |
| L1-N contra L2-N | as duas 114 – 126 V | Uma sobe e a outra desce com carga = problema no neutro |
| Interruptor fechado / fusível bom | perto de 0 ohm | OL = aberto |
| Transformador da campainha | 10 – 24 V AC | 16 V é o mais comum |
| Resistência do aquecedor (240 V) | 4500 W = 12.8 ohms | 3500 W = 16.5 ohms |
| Carga contínua (regra dos 80%) | 12 A / 16 A | Em disjuntor de 15 A / 20 A |
| Test | Normal | Notes |
|---|---|---|
| 120 V outlet, hot-neutral | 114 – 126 V | ANSI C84.1 Range A for 120 V |
| Hot-ground | same as hot-neutral | About 0 V = no ground |
| Neutral-ground | under 2 V | Higher under load = loose or long neutral |
| 240 V, L1-L2 | 228 – 252 V | ANSI C84.1 Range A for 240 V |
| L1-N vs L2-N | both 114 – 126 V | One up, one down under load = neutral problem |
| Closed switch / good fuse | about 0 ohms | OL = open |
| Doorbell transformer | 10 – 24 V AC | 16 V is the most common |
| Water heater element (240 V) | 4500 W = 12.8 ohms | 3500 W = 16.5 ohms |
| Continuous load (80% rule) | 12 A / 16 A | On a 15 A / 20 A breaker |
| Test | Normal | Notes |
|---|---|---|
| 120 V outlet, hot-neutral | 114 – 126 V | ANSI C84.1 Range A for 120 V |
| Hot-ground | same as hot-neutral | About 0 V = no ground |
| Neutral-ground | under 2 V | Higher under load = loose or long neutral |
| 240 V, L1-L2 | 228 – 252 V | ANSI C84.1 Range A for 240 V |
| L1-N vs L2-N | both 114 – 126 V | One up, one down under load = neutral problem |
| Closed switch / good fuse | about 0 ohms | OL = open |
| Doorbell transformer | 10 – 24 V AC | 16 V is the most common |
| Water heater element (240 V) | 4500 W = 12.8 ohms | 3500 W = 16.5 ohms |
| Continuous load (80% rule) | 12 A / 16 A | On a 15 A / 20 A breaker |
Os vinte chamados mais comuns
A tabela traz a causa que aparece primeiro e a medida que costuma resolver a dúvida. No guia, cada chamado tem um cartão com três causas em ordem, o teste completo, o conserto de sempre e a faixa de tempo e preço.
| # | Chamado | Causa mais comum | O que medir primeiro | Tempo | Preço |
|---|---|---|---|---|---|
| 1 | Tomadas mortas num cômodo | GFCI desarmado em outro cômodo | Fase-neutro na tomada; todos os GFCI do circuito | 0.5 – 1.5 h | $100 – $250 |
| 2 | GFCI não rearma | Sem energia no LINE ou LINE e LOAD trocados | Tensão nos bornes LINE; rearmar com o LOAD desligado | 0.5 – 1.5 h | $120 – $270 |
| 3 | GFCI desarma toda hora | Água na caixa externa | Tirar todas as cargas; desligar o LOAD e testar | 1 – 2.5 h | $150 – $350 |
| 4 | Disjuntor desarma depois de um tempo | Sobrecarga no circuito | Alicate amperímetro na fase com as cargas normais | 1 – 2 h | $150 – $400 |
| 5 | Disjuntor desarma na hora de religar | Curto: fio prensado, prego ou parafuso | Ohms fase-neutro e fase-terra; dividir o circuito | 1 – 3 h | $150 – $450 |
| 6 | AFCI desarmando à toa | Neutro encostando no terra | Indicador do disjuntor; ohms neutro-terra isolado | 1 – 3 h | $150 – $400 |
| 7 | Uma lâmpada pisca | LED que não serve para o dimmer | Lâmpada boa; lista de LED do dimmer; emendas | 0.5 – 1 h | $100 – $250 |
| 8 | A casa toda escurece ou clareia | Neutro da entrada frouxo ou aberto | L1-N e L2-N no quadro com carga grande ligada | 1 – 2 h | $150 – $500 |
| 9 | Metade da casa sem luz | Perdeu uma fase da concessionária | L1-L2 e cada fase ao neutro no geral | 1 – 2 h | $150 – $400 |
| 10 | Tomada quente ou cheiro de queimado | Borne frouxo ou backstab | Desligar; plástico derretido, fio escuro, termômetro IR | 1 – 2 h | $150 – $350 |
| 11 | Tomada solta faísca ou não segura o plugue | Contatos gastos | Bornes com tudo desligado | 0.5 – 1 h | $100 – $215 |
| 12 | Interruptor não faz nada | Lâmpada ou luminária queimada | Continuidade no interruptor; tensão na luminária | 0.5 – 1 h | $100 – $250 |
| 13 | Three-way só funciona de um lado | Comum e traveler trocados | Achar o parafuso comum; continuidade ao virar | 0.5 – 1.5 h | $120 – $300 |
| 14 | Ventilador de teto parado ou lento | Capacitor fraco ou chave de corrente | Tensão nos fios do ventilador; valor do capacitor | 1 – 2 h | $100 – $300 |
| 15 | Campainha muda | Transformador queimado | Saída do transformador; jumper no botão | 0.5 – 1.5 h | $100 – $250 |
| 16 | Detector de fumaça apitando | Bateria fraca ou aparelho com mais de 10 anos | Data no verso; teste em cada um | 0.5 – 1 h | $70 – $150 / unit |
| 17 | Aquecedor elétrico sem água quente | Limite (ECO) desarmado | Resistência em ohms; 240 V no aquecedor | 1 – 2 h | $150 – $450 |
| 18 | Tomada externa ou luz do jardim morta | GFCI desarmado (garagem ou banheiro) | Achar o GFCI; água na caixa; timer ou fotocélula | 0.5 – 1.5 h | $120 – $300 |
| 19 | Choquinho em aparelho ou torneira | Falta de terra ou de equipotencialização | Fase-terra, neutro-terra, polaridade, carcaça-terra | 1 – 3 h | $150 – $500 |
| 20 | Tomada de 3 pinos sem terra | Fiação antiga de 2 fios | Testador mostra terra aberto; fase-terra perto de 0 V | 0.5 – 2 h / outlet | $50 – $300 / outlet |
| # | Call | Most common cause | Test first | Time | Price |
|---|---|---|---|---|---|
| 1 | Dead outlets in one room | Tripped GFCI upstream (bath, garage, kitchen, outdoor) | Hot-neutral at the dead outlet (expect about 120 V). Check every GFCI on the circuit, then open the last outlet that still works. | 0.5 – 1.5 h | $100 – $250 |
| 2 | GFCI won’t reset | No power on the LINE side | Voltage at the LINE terminals. Cap the LOAD wires and try again: if it resets now, the fault is downstream. | 0.5 – 1.5 h | $120 – $270 |
| 3 | GFCI keeps tripping | Water in an outdoor box or receptacle | Unplug everything, reset, add loads one at a time. Then disconnect LOAD and retest; insulation test the downstream run. | 1 – 2.5 h | $150 – $350 |
| 4 | Breaker trips after a while | Overload: too much on one circuit | Clamp meter on the hot at the panel with the normal loads on. 80% rule: 12 A continuous on 15 A, 16 A on 20 A. | 1 – 2 h | $150 – $400 |
| 5 | Breaker trips the moment you reset | Short circuit: pinched wire, nail or screw in a cable | Breaker OFF, wires off the breaker. Ohms hot-neutral and hot-ground on the run. Split the circuit at a midpoint to isolate. | 1 – 3 h | $150 – $450 |
| 6 | AFCI nuisance trips | Neutral touching ground somewhere | Read the trip indicator if the breaker has one. With the circuit isolated, ohms neutral-ground should read open. | 1 – 3 h | $150 – $400 |
| 7 | One light flickers | Loose bulb, or LED not made for that dimmer | Try a known good bulb and check the dimmer’s LED list. Power off: open the switch and fixture, inspect every splice. | 0.5 – 1 h | $100 – $250 |
| 8 | Whole house dims, or lights get brighter | Loose or open service neutral | At the main, L1-N and L2-N while a big 120 V load runs. One leg going up while the other goes down = neutral problem. | 1 – 2 h | $150 – $500 |
| 9 | Half the house is dead | One leg lost from the utility | At the main: L1-L2 about 240 V, each leg to neutral about 120 V. A lost leg reads 0 V or low on one side. | 1 – 2 h | $150 – $400 |
| 10 | Hot outlet or switch, burning smell | Loose terminal or backstab | Power off first. Look for melted plastic and dark insulation; IR thermometer on loaded devices of the same circuit. | 1 – 2 h | $150 – $350 |
| 11 | Outlet sparks or won’t hold a plug | Worn contacts | A tiny spark when plugging in a load can be normal; scorch marks are not. Check the terminals with power off. | 0.5 – 1 h | $100 – $215 |
| 12 | Switch does nothing | Dead bulb or fixture | Power off: continuity across the switch in ON. Power on: voltage at the switch line terminal and at the fixture. | 0.5 – 1 h | $100 – $250 |
| 13 | 3-way works from only one side | Common and traveler swapped at one switch | Find the common screw (dark color) on each switch. Power off: continuity common-to-traveler as you flip it. | 0.5 – 1.5 h | $120 – $300 |
| 14 | Ceiling fan dead or slow | Pull-chain switch failed | Voltage at the fan leads; check the wall switch and the receiver; compare the capacitor to its label value. | 1 – 2 h | $100 – $300 |
| 15 | Doorbell is silent | Transformer dead | Transformer output: usually 10 – 24 V AC (16 V is common). Jumper the button terminals: the chime should ring. | 0.5 – 1.5 h | $100 – $250 |
| 16 | Smoke alarms chirping | Low battery | Read the date on the back of each alarm. Press test on each one: interconnected alarms should all sound. | 0.5 – 1 h | $70 – $150 / unit |
| 17 | Electric water heater, no hot water | High-limit (ECO) tripped | Power off. Element ohms at 240 V: 4500 W = 12.8 ohms, 3500 W = 16.5 ohms; open = bad. Check 240 V at the heater. | 1 – 2 h | $150 – $450 |
| 18 | Outdoor outlet or yard lights dead | Tripped GFCI (often in the garage or a bath) | Find the GFCI that protects the outdoor circuit; look for water in the box; test the timer or photocell. | 0.5 – 1.5 h | $120 – $300 |
| 19 | Tingle or shock from appliance or faucet | Missing ground or bonding | Hot-ground and neutral-ground at the outlet; plug-in tester for polarity; volts from the appliance frame to ground. | 1 – 3 h | $150 – $500 |
| 20 | 3-prong outlets with no ground | Old 2-wire wiring | Plug-in tester shows open ground; hot-ground reads about 0 V while hot-neutral reads about 120 V. | 0.5 – 2 h / outlet | $50 – $300 / outlet |
| # | Call | Most common cause | Test first | Time | Price |
|---|---|---|---|---|---|
| 1 | Dead outlets in one room | Tripped GFCI upstream (bath, garage, kitchen, outdoor) | Hot-neutral at the dead outlet (expect about 120 V). Check every GFCI on the circuit, then open the last outlet that still works. | 0.5 – 1.5 h | $100 – $250 |
| 2 | GFCI won’t reset | No power on the LINE side | Voltage at the LINE terminals. Cap the LOAD wires and try again: if it resets now, the fault is downstream. | 0.5 – 1.5 h | $120 – $270 |
| 3 | GFCI keeps tripping | Water in an outdoor box or receptacle | Unplug everything, reset, add loads one at a time. Then disconnect LOAD and retest; insulation test the downstream run. | 1 – 2.5 h | $150 – $350 |
| 4 | Breaker trips after a while | Overload: too much on one circuit | Clamp meter on the hot at the panel with the normal loads on. 80% rule: 12 A continuous on 15 A, 16 A on 20 A. | 1 – 2 h | $150 – $400 |
| 5 | Breaker trips the moment you reset | Short circuit: pinched wire, nail or screw in a cable | Breaker OFF, wires off the breaker. Ohms hot-neutral and hot-ground on the run. Split the circuit at a midpoint to isolate. | 1 – 3 h | $150 – $450 |
| 6 | AFCI nuisance trips | Neutral touching ground somewhere | Read the trip indicator if the breaker has one. With the circuit isolated, ohms neutral-ground should read open. | 1 – 3 h | $150 – $400 |
| 7 | One light flickers | Loose bulb, or LED not made for that dimmer | Try a known good bulb and check the dimmer’s LED list. Power off: open the switch and fixture, inspect every splice. | 0.5 – 1 h | $100 – $250 |
| 8 | Whole house dims, or lights get brighter | Loose or open service neutral | At the main, L1-N and L2-N while a big 120 V load runs. One leg going up while the other goes down = neutral problem. | 1 – 2 h | $150 – $500 |
| 9 | Half the house is dead | One leg lost from the utility | At the main: L1-L2 about 240 V, each leg to neutral about 120 V. A lost leg reads 0 V or low on one side. | 1 – 2 h | $150 – $400 |
| 10 | Hot outlet or switch, burning smell | Loose terminal or backstab | Power off first. Look for melted plastic and dark insulation; IR thermometer on loaded devices of the same circuit. | 1 – 2 h | $150 – $350 |
| 11 | Outlet sparks or won’t hold a plug | Worn contacts | A tiny spark when plugging in a load can be normal; scorch marks are not. Check the terminals with power off. | 0.5 – 1 h | $100 – $215 |
| 12 | Switch does nothing | Dead bulb or fixture | Power off: continuity across the switch in ON. Power on: voltage at the switch line terminal and at the fixture. | 0.5 – 1 h | $100 – $250 |
| 13 | 3-way works from only one side | Common and traveler swapped at one switch | Find the common screw (dark color) on each switch. Power off: continuity common-to-traveler as you flip it. | 0.5 – 1.5 h | $120 – $300 |
| 14 | Ceiling fan dead or slow | Pull-chain switch failed | Voltage at the fan leads; check the wall switch and the receiver; compare the capacitor to its label value. | 1 – 2 h | $100 – $300 |
| 15 | Doorbell is silent | Transformer dead | Transformer output: usually 10 – 24 V AC (16 V is common). Jumper the button terminals: the chime should ring. | 0.5 – 1.5 h | $100 – $250 |
| 16 | Smoke alarms chirping | Low battery | Read the date on the back of each alarm. Press test on each one: interconnected alarms should all sound. | 0.5 – 1 h | $70 – $150 / unit |
| 17 | Electric water heater, no hot water | High-limit (ECO) tripped | Power off. Element ohms at 240 V: 4500 W = 12.8 ohms, 3500 W = 16.5 ohms; open = bad. Check 240 V at the heater. | 1 – 2 h | $150 – $450 |
| 18 | Outdoor outlet or yard lights dead | Tripped GFCI (often in the garage or a bath) | Find the GFCI that protects the outdoor circuit; look for water in the box; test the timer or photocell. | 0.5 – 1.5 h | $120 – $300 |
| 19 | Tingle or shock from appliance or faucet | Missing ground or bonding | Hot-ground and neutral-ground at the outlet; plug-in tester for polarity; volts from the appliance frame to ground. | 1 – 3 h | $150 – $500 |
| 20 | 3-prong outlets with no ground | Old 2-wire wiring | Plug-in tester shows open ground; hot-ground reads about 0 V while hot-neutral reads about 120 V. | 0.5 – 2 h / outlet | $50 – $300 / outlet |
Três chamados que não podem esperar
| Chamado urgente | Por quê |
|---|---|
| A casa toda escurece ou clareia | Neutro aberto manda tensão alta para um lado da casa e queima eletrônicos. Concessionária no lado dela, quadro no seu. |
| Tomada quente, cheiro de queimado | Ligação frouxa esquenta até derreter. Desligue o circuito antes de qualquer coisa. |
| Choquinho em aparelho ou torneira | Falta de terra ou de equipotencialização deixa tensão onde a pessoa encosta. Tire o aparelho de uso. |
| Urgent call | Why |
|---|---|
| Whole house dims, or lights get brighter | Utility for their side; tighten or repair the neutral in the panel. Urgent: it can burn electronics. |
| Hot outlet or switch, burning smell | Cut back to clean wire, new device; CO/ALR devices or listed AL-to-CU connectors on aluminum. |
| Tingle or shock from appliance or faucet | Restore grounding and bonding, fix polarity, take the appliance out of service. |
| Urgent call | Why |
|---|---|
| Whole house dims, or lights get brighter | Utility for their side; tighten or repair the neutral in the panel. Urgent: it can burn electronics. |
| Hot outlet or switch, burning smell | Cut back to clean wire, new device; CO/ALR devices or listed AL-to-CU connectors on aluminum. |
| Tingle or shock from appliance or faucet | Restore grounding and bonding, fix polarity, take the appliance out of service. |
Na página seguinte estão o guia para baixar, como montar o preço do chamado, a ficha de atendimento e as dúvidas mais comuns.
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Guia dos 20 chamados do eletricista: o que medir, conserto, tempo e preço, em inglês
