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  <element name="BusinessCombinationConsiderationTransferredOrToBeTransferredCashAndLiabilitiesIncurred" id="pwr_BusinessCombinationConsiderationTransferredOrToBeTransferredCashAndLiabilitiesIncurred" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetTangibleAssets" id="pwr_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNetTangibleAssets" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CanadianAndAustralianDollarsMember" id="pwr_CanadianAndAustralianDollarsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CashPaidForOtherIntangibles" id="pwr_CashPaidForOtherIntangibles" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CentralStatesPlanMember" id="pwr_CentralStatesPlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ChangeInContractEstimatesImpactOnOperatingResults" id="pwr_ChangeInContractEstimatesImpactOnOperatingResults" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ChangeInContractEstimatesImpactOnOperatingResultsValueGainsIdentifiedThatOffsetAgainstLossesDisclosed" id="pwr_ChangeInContractEstimatesImpactOnOperatingResultsValueGainsIdentifiedThatOffsetAgainstLossesDisclosed" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CommitmentAndContingenciesLineItems" id="pwr_CommitmentAndContingenciesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CommitmentAndContingenciesTable" id="pwr_CommitmentAndContingenciesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="CommonStockAvailableForAwardsPursuantToPlan" id="pwr_CommonStockAvailableForAwardsPursuantToPlan" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CommonStockWithheldForSettlementOfEmployeeTaxLiabilitiesMember" id="pwr_CommonStockWithheldForSettlementOfEmployeeTaxLiabilitiesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ContractValueOfProject" id="pwr_ContractValueOfProject" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CorporateAndNonAllocatedCostsMember" id="pwr_CorporateAndNonAllocatedCostsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CrossDefaultProvisions" id="pwr_CrossDefaultProvisions" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DecreaseInFairValueOfReportingUnitsConsideredForImpairmentCalculation" id="pwr_DecreaseInFairValueOfReportingUnitsConsideredForImpairmentCalculation" type="num:percentItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DescriptionOfNewAccountingPronouncementsNotYetAdoptedPolicyTextBlock" id="pwr_DescriptionOfNewAccountingPronouncementsNotYetAdoptedPolicyTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DiscontinuedOperationsDisposedOfBySaleAbstract" id="pwr_DiscontinuedOperationsDisposedOfBySaleAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DisposalGroupIncludingDiscontinuedOperationAmortizationOfIntangibleAssets" id="pwr_DisposalGroupIncludingDiscontinuedOperationAmortizationOfIntangibleAssets" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DocumentAndEntityInformationAbstract" id="pwr_DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DomesticBankAccountsMember" id="pwr_DomesticBankAccountsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DomesticJointVenturesMember" id="pwr_DomesticJointVenturesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ElectricPowerDivisionMember" id="pwr_ElectricPowerDivisionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ElectricPowerInfrastructureMember" id="pwr_ElectricPowerInfrastructureMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ElectricPowerInfrastructureServicesBusinessMember" id="pwr_ElectricPowerInfrastructureServicesBusinessMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EmployersLiabilityInsuranceClaimsDeductible" id="pwr_EmployersLiabilityInsuranceClaimsDeductible" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EscrowedFundsToCoverMultipleEmployerPlansLiabilityOfAcquiredCompany" id="pwr_EscrowedFundsToCoverMultipleEmployerPlansLiabilityOfAcquiredCompany" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EstimatedCostToCompleteBondedProjects" id="pwr_EstimatedCostToCompleteBondedProjects" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExcessOfBaseRateDomesticBorrowingsOnlyMember" id="pwr_ExcessOfBaseRateDomesticBorrowingsOnlyMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExcessOfEurocurrencyRateApplicableToDomesticBorrowingsOnlyMember" id="pwr_ExcessOfEurocurrencyRateApplicableToDomesticBorrowingsOnlyMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExcessOfEuroCurrencyRateMember" id="pwr_ExcessOfEuroCurrencyRateMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExcessOfEuroCurrencyRateOfCreditAgreementForForeignBorrowingsMember" id="pwr_ExcessOfEuroCurrencyRateOfCreditAgreementForForeignBorrowingsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExcessOfFederalFundsRateMember" id="pwr_ExcessOfFederalFundsRateMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExchangeableSharesAssociatedWithSeriesFPreferredStockMember" id="pwr_ExchangeableSharesAssociatedWithSeriesFPreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExchangeableSharesAssociatedWithSeriesGPreferredStockMember" id="pwr_ExchangeableSharesAssociatedWithSeriesGPreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExchangeableSharesForCommonStockMember" id="pwr_ExchangeableSharesForCommonStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExchangeableSharesNotAssociatedWithPreferredStockMember" id="pwr_ExchangeableSharesNotAssociatedWithPreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ExchangeableStockSharesOutstanding" id="pwr_ExchangeableStockSharesOutstanding" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="FiberOpticLicensingMember" id="pwr_FiberOpticLicensingMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ForecastedReturnsOfCapitalFromUnconsolidatedAffiliatesInOneYear" id="pwr_ForecastedReturnsOfCapitalFromUnconsolidatedAffiliatesInOneYear" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ForeignBankAccountsMember" id="pwr_ForeignBankAccountsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ForeignOperationsMember" id="pwr_ForeignOperationsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="FourthAmendedAndRestatedMember" id="pwr_FourthAmendedAndRestatedMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="GeneralLiabilityInsuranceClaimsDeductible" id="pwr_GeneralLiabilityInsuranceClaimsDeductible" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="HealthCareDeductible" id="pwr_HealthCareDeductible" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IntangibleAssetsDisclosureAbstract" id="pwr_IntangibleAssetsDisclosureAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IntangibleLiabilityDisclosureAbstract" id="pwr_IntangibleLiabilityDisclosureAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="InvestmentsInAffiliatesAndOtherEntitiesPolicyTextBlock" id="pwr_InvestmentsInAffiliatesAndOtherEntitiesPolicyTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="InvestmentsInJointVenturesMember" id="pwr_InvestmentsInJointVenturesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LengthOfTransmissionLine" id="pwr_LengthOfTransmissionLine" type="num:lengthItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LettersOfCreditAndBankGuaranteesMember" id="pwr_LettersOfCreditAndBankGuaranteesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LongTermDebtWeightedAverageInterestRateDuringPeriod" id="pwr_LongTermDebtWeightedAverageInterestRateDuringPeriod" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LorenzoBentonvTelecomNetworkSpecialistsIncMember" id="pwr_LorenzoBentonvTelecomNetworkSpecialistsIncMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LossContingencyAccrualPaymentsAmount" id="pwr_LossContingencyAccrualPaymentsAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LossContingencyDamagesSoughtValueByPlaintiffForClassDamages" id="pwr_LossContingencyDamagesSoughtValueByPlaintiffForClassDamages" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LossContingencyDamagesSoughtValueByPlaintiffForLegalFees" id="pwr_LossContingencyDamagesSoughtValueByPlaintiffForLegalFees" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="MinimumNumberOfSharesThatCanBeExchangedByExchangeableShareholdersUnlessNumberOfRemainingExchangeableSharesRegisteredInNameOfHolderIsLess" id="pwr_MinimumNumberOfSharesThatCanBeExchangedByExchangeableShareholdersUnlessNumberOfRemainingExchangeableSharesRegisteredInNameOfHolderIsLess" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="MultiemployerPlanWithdrawalObligationAmountSuggestedByPlanDifferentThanAmountRecordedByCompany" id="pwr_MultiemployerPlanWithdrawalObligationAmountSuggestedByPlanDifferentThanAmountRecordedByCompany" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NetPositionMember" id="pwr_NetPositionMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfAgencies" id="pwr_NumberOfAgencies" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfCommonStockSharesReceivedByRsuHolder" id="pwr_NumberOfCommonStockSharesReceivedByRsuHolder" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfCustomersRepresentingTenPercentOrMoreOfConcentrationRisk" id="pwr_NumberOfCustomersRepresentingTenPercentOrMoreOfConcentrationRisk" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfProjectsWithSignificantLosses" id="pwr_NumberOfProjectsWithSignificantLosses" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfReportingUnitsImpactedByImpairmentCharges" id="pwr_NumberOfReportingUnitsImpactedByImpairmentCharges" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfSharesOfCommonStockReceivedForEachExchangeableShare" id="pwr_NumberOfSharesOfCommonStockReceivedForEachExchangeableShare" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OilAndGasInfrastructureServicesBusinessMember" id="pwr_OilAndGasInfrastructureServicesBusinessMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OilAndGasInfrastructureServicesMember" id="pwr_OilAndGasInfrastructureServicesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OilAndGasMember" id="pwr_OilAndGasMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OptionToIncreaseRevolvingCommitmentsUnderCreditAgreement" id="pwr_OptionToIncreaseRevolvingCommitmentsUnderCreditAgreement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OrganizationAndDescriptionOfBusinessLineItems" id="pwr_OrganizationAndDescriptionOfBusinessLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OrganizationAndDescriptionOfBusinessTable" id="pwr_OrganizationAndDescriptionOfBusinessTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="OtherCommitmentsEngineeringProcurementAndConstructionElectricTransmissionProjectMember" id="pwr_OtherCommitmentsEngineeringProcurementAndConstructionElectricTransmissionProjectMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OtherCommitmentsPlannedOilAndGasInfrastructureProjectsMember" id="pwr_OtherCommitmentsPlannedOilAndGasInfrastructureProjectsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OtherComprehensiveIncomeOtherTax" id="pwr_OtherComprehensiveIncomeOtherTax" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OtherLongTermDebtMember" id="pwr_OtherLongTermDebtMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OutstandingPerformanceBondsAmount" id="pwr_OutstandingPerformanceBondsAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PercentageOfCapitalStockOfDirectForeignSubsidiariesRequiredToSecureCreditAgreement" id="pwr_PercentageOfCapitalStockOfDirectForeignSubsidiariesRequiredToSecureCreditAgreement" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PercentageOfForeignRevenue" id="pwr_PercentageOfForeignRevenue" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PercentChangeInContractEstimatesImpactOnOperatingResultsIsLessThanThisPercentage" id="pwr_PercentChangeInContractEstimatesImpactOnOperatingResultsIsLessThanThisPercentage" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PerformanceBasedAwardPerformancePercentage" id="pwr_PerformanceBasedAwardPerformancePercentage" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PerformanceLettersOfCreditMember" id="pwr_PerformanceLettersOfCreditMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PerformanceUnitsMember" id="pwr_PerformanceUnitsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PeriodAfterAccountsReceivableAreTreatedAsDelinquent" id="pwr_PeriodAfterAccountsReceivableAreTreatedAsDelinquent" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PeriodRelatedToOutstandingAccountsReceivableForAnalysisOfAllowanceForDoubtfulAccounts" id="pwr_PeriodRelatedToOutstandingAccountsReceivableForAnalysisOfAllowanceForDoubtfulAccounts" type="us-types:durationStringItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="QuantaElectricPowerInfrastructureServicesSegmentMember" id="pwr_QuantaElectricPowerInfrastructureServicesSegmentMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ReductionInCompanyMaximumFundedDebtAndMaximumSeniorDebtByAllCashAndCashEquivalentsInExcessOfAmount" id="pwr_ReductionInCompanyMaximumFundedDebtAndMaximumSeniorDebtByAllCashAndCashEquivalentsInExcessOfAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RepurchaseProgram2015OpenMarketPurchasesAndAcceleratedShareRepurchaseProgramMember" id="pwr_RepurchaseProgram2015OpenMarketPurchasesAndAcceleratedShareRepurchaseProgramMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RestrictedStockAndRestrictedStockUnitsToBeSettledInCommonStockMember" id="pwr_RestrictedStockAndRestrictedStockUnitsToBeSettledInCommonStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RestrictedStockUnitsToBeSettledInCashMember" id="pwr_RestrictedStockUnitsToBeSettledInCashMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RevenueRecognitionPercentageOfCompletionPercentComplete" id="pwr_RevenueRecognitionPercentageOfCompletionPercentComplete" type="num:percentItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RevenueRecognitionTable" id="pwr_RevenueRecognitionTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="RevenueRecognizedForCurrentPeriodLossesLineItems" id="pwr_RevenueRecognizedForCurrentPeriodLossesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RevolvingLoansAndLetterOfCreditInAlternativeCurrenciesMember" id="pwr_RevolvingLoansAndLetterOfCreditInAlternativeCurrenciesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsByMajorClassTableTextBlock" id="pwr_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsByMajorClassTableTextBlock" type="nonnum:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SeriesFAndSeriesGPreferredStockMember" id="pwr_SeriesFAndSeriesGPreferredStockMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SummaryOfSignificantAccountingPoliciesLineItems" id="pwr_SummaryOfSignificantAccountingPoliciesLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="SummaryOfSignificantAccountingPoliciesTable" id="pwr_SummaryOfSignificantAccountingPoliciesTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="SwingLinesLoanMember" id="pwr_SwingLinesLoanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndElevenPlanMember" id="pwr_TwoThousandAndElevenPlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndSevenPlanMember" id="pwr_TwoThousandAndSevenPlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandFifteenRepurchaseProgramMember" id="pwr_TwoThousandFifteenRepurchaseProgramMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandFifteenRepurchaseProgramOpenMarketPurchasesMember" id="pwr_TwoThousandFifteenRepurchaseProgramOpenMarketPurchasesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandThirteenRepurchaseProgramAndOpenMarketRepurchasesMember" id="pwr_TwoThousandThirteenRepurchaseProgramAndOpenMarketRepurchasesMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandThirteenRepurchaseProgramMember" id="pwr_TwoThousandThirteenRepurchaseProgramMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="VehicleFleetCommittedCapitalMember" id="pwr_VehicleFleetCommittedCapitalMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="WorkersCompensationInsuranceClaimsDeductible" id="pwr_WorkersCompensationInsuranceClaimsDeductible" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
</schema>
