InvestigationReport

BASECClient ElectricalSafetyFirstUnit331MetalBoxFactory30GreatGuildfordStreetLondonSE10HS

ReportNo. NAC069Issue2NumberofpagesinthisReport:26

IssueDate 30November2015

Reference NAC069Issue2

ItemsInvestigated: 6samplesofElectricCableasdetailedwithinthisReport

Investigations: AsdetailedwithinthisReport

Findings: AsdetailedwithinthisReport

Authorisedby:

Investigationsby:

IssueDate:

JHodge ChiefExecutive

IMcGuinness LaboratoryManager

30November2015

ThefindingspresentedinthisInvestigationReportrelateonlytotheitemsinvestigatedandtothespecificexaminationsandtestscarriedout.ThisInvestigationReportdoesnotrepresentanyApprovalorCertificationbyBASECofanyproductorofanyassociatedmanufacturer,oranyrecommendationastofitnessforpurposeoruseinanyparticularmanner.ThisInvestigationReportshallnotbereproducedexceptinfull,withoutwrittenapprovalofBASEC.

BritishApprovalsServiceforCablesPresleyHouse,PresleyWayCrownhill,MiltonKeynesMK80ESUKT:01908267300F:01908267255E:mail@basec.org.ukW:www.basec.org.uk

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Datetestingcommenced:01/10/14 Datetestingcompleted:27/11/15 Testedby:IMcGuinness

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1. Introduction Thisreportrelatestoinvestigativetestsconductedonsamplesofsixtypesofelectriccable commonly used in domestic installations in the UK, as agreedwith ElectricalSafetyFirst. The investigativetestingwasdesignedtosimulatebothshortandlongtermimmersioninvariousliquidsthatcouldbeexperiencedbyinstalledcablesduringperiodsofflooding.Thisreportappliesonlytotheparticularsamplesofcabletestedandtothespecifictest protocols carried out and detailed within the report. Interpretation andextrapolation of these findings to different types of cable, different liquid types orconditions,ortogreaterdepthsofwaterisnotrecommendedwithoutfurtherwork.The investigative testing was conducted without energising the cables, except forconducting specific cable condition tests as detailed in the report. The possibleeffects of impingement of water on energised cable installations have not beeninvestigated. Attention is drawn to the potential safety hazards of electricity andwaterincombination.2. CableTypesandSamplesThe cable types used in the investigative testingwere chosen to reflect a range oftypesandsizesofbuildingwiringcommonlyusedindomesticinstallationsintheUK.Thesamplesusedwerenottestedforconformitytotherelevantcablespecificationsbeforebeingsubjectedtotheinvestigativetesting.Allthesamplescarriedarelevantapproval marking (e.g., BASEC) on the cable, and were therefore presumed toconform to the relevant cable specifications, as detailed below. Nothing emergedduringthetestingorexaminationtosuggestthatanyofthesamplesusedwerenotinconformitywiththerelevantspecifications.The cable samples were chosen at random from readily available stock withoutreference to the identity of, or consultationwith, theirmanufacturer, andhence itwouldnotbeappropriateinthisreporttoidentifythemanufacturersoftheparticularcablesused. Therearesometimesminordifferencesbetweencablesfromdifferentmanufacturersarisingfromtheiruseofdifferentlysourcedprecursormaterialsandintheir manufacturing processes, but the samples in question were all declared toconform to the relevant cable specifications. A comprehensive review of theperformance of cable types from a range ofmanufacturers is beyond the scope ofthisworkandreport.

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Thetypesofelectriccableusedintheinvestigativetestingwereasfollows:A SinglecorePVCbuildingwire,solidconductor.

1X1.5mm²singlecoreclass1solidconductorwithblueinsulation.Harmonisedcodedesignation:H07V-U,UKcablecode:6491X.Specification:BSEN50525-2-31:2011,clause4.1,rated450/750V.

B SinglecorePVCbuildingwire,solidconductor.

1X2.5mm²singlecoreclass1conductorwithbrowninsulation.Harmonisedcodedesignation:H07V-U,UKcablecode:6491X.Specification:BSEN50525-2-31:2011,clause4.1,rated450/750V.

C SinglecorePVCbuildingwire,strandedconductor.

1X4.0mm²singlecoreclass2conductorwithgreen-and-yellowinsulation.Harmonisedcodedesignation:H07V-R,UKcablecode:6491X.Specification:BSEN50525-2-31:2011,clause4.1,rated450/750V.

D TwinandearthPVCcable,solidconductors,withsolidCPC.

2x2.5mm2twin&earthclass1conductorswithgreysheath.UKcablecode:6242Y.Specification:BS6004:2012,table4,rated300/500V.

E TwinandearthPVCcable,strandedconductors,withsolidCPC.

2x2.5mm2twin&earthclass2conductorswithgreysheath.UKcablecode:6242Y.Specification:BS6004:2012,table5,rated300/500V.

F TwinandearthLSHFcable,solidconductors,withsolidCPC.

2x2.5mm2twin&earthclass1conductorswithwhitesheath.UKcablecode:6242B.Specification:BS7211:2012,table5,rated300/500V.

Notes:

TypesAtoEweremadeofPVCmaterials;typeFwasmadeoflowsmokehalogenfree(LSHF)material.

TypesA,B,DandFwereofsolidconductorconstruction;typesCandEwereofstrandedconstruction.

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3. TestProtocolsThefollowingtestprotocolswereemployedtoinvestigatethepenetrationofwaterintoimmersedopenendsofcables,andtoinvestigatetheelectricalperformanceofthecablesafterorduringimmersion,andtoascertainanydegradationintheperformanceofthesheathingmaterial.Protocol1-Wicking:

SamplesofcableoftypesAtoF,each2mlong,weresuspendedverticallyinliquidinthreeseparatetankscontaining(a)clean,(b)saltyand(c)siltywater,withalengthof20cm immersed below the surface. After an immersion period of oneweek, eachsamplewasremovedfromtherelevanttesttank,cutopenevery2cmstartingattheimmersed end and visually inspected for the presence of water inside the cable,between the conductor and insulation and (where appropriate) between theinsulation/CPCandthesheath.Protocol2-Penetration:

SamplesofcableoftypesAtoF,each5mlong,weresuspendedhorizontallyinliquidinthreeseparatetankscontaining(a)clean,(b)saltyand(c)siltywater.Oneendofeach sample was kept 1m clear of the liquid, with the remainder coiled at animmersion depth of 1m. After an immersion period of 1 week, each sample wasremovedfromtherelevanttesttank,cutopenevery10cmandvisuallyinspectedforthe presence ofwater inside the cable, between the conductor and insulation and(whereappropriate)betweentheinsulation/CPCandthesheath.Protocol3–InsulationResistanceonDrying:

SamplesofcableoftypesDtoF,each2mlongwith1mimmersed,weresuspendedvertically in liquid inthreeseparatetankscontaining(A)clean,(B)saltyand(C)siltywater. Afteran immersionperiodof24hours,eachsamplewasremovedfromtherelevanttankandallowedtodryinaverticalorientation.Theinsulationresistanceofeach sample was measured between the phase and neutral conductors bondedtogether and the circuit protective conductor, using a 500Vdc insulation resistancetester.Thistestwasrepeatedattimes15min,30min,45min,4hrs,24hrs,48hrsand1weekafterremovalfromtheliquid.

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Protocol4–MediumTermImmersionInsulationResistance:

Samplesofcableof typesEandF,each5mlong,weresuspended in liquid inthreeseparatetankscontaining (A)clean, (B)saltyand(C)siltywater. Thesampleswerecoiled and suspended at a depth of 1m, with both ends kept clear of the liquidsurface.Duringtheperiodofimmersiontheinsulationresistanceofeachsamplewasmeasuredbetweentheconductorsandcircuitprotectiveconductorbondedtogetherandthe immersion liquid,usinga500Vdc insulationresistance tester. Thesampleswere also subjected to high voltage withstand test at 2000Vac between theconductorsandtheimmersionliquid. Themeasurementswererepeatedattimes1week,2weeks,1monthand3monthsafterimmersion.Protocol5–ModelFlood,InsulationResistanceonDrying:

Samples of cable of types D, E and F, each 5m long, with both ends stripped fornormalaccessorytermination(100mmofinsulationand12mmcoppervisible),weresuspendedinliquidinthreeseparatetankscontaining(A)clean,(B)saltyand(C)siltywater,atotalofninesamples.Thesampleswerecoiledandsuspendedatadepthof1m,withbothendsimmersedatthesamedepth.Thesampleswereimmersedforaperiod of one week, and then removed and left to dry naturally at ambienttemperature.Theexposedandstrippedendsweredriedmanuallywithtissuebeforethe firstpost-immersion test. During thedryingperiod the insulation resistanceofeach sample was measured between each conductor and the circuit protectiveconductor, using a 500Vdc insulation resistance tester. The measurements wererepeateddailyandthenweeklyforseveralweeksafterremovalfromthetanks.Oncompletionofthemeasurements,thesampleswereslitandinternallyexamined.Protocol5workwascompletedasaseparateworkitemfollowingthecompletionofworkonProtocols1to4.

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Immersionliquids:(a)Cleanwaterwaspotabletapwater,takenfromlocalMiltonKeynesmainswater,withoutanyfiltering,softening,deionisationorothertreatment.Therewasnoagitationinthetankcontainingthisliquid.(b)Saltywaterwaspotabletapwater(asabove)withsufficientNaCladdedtogiveanapproximatesalinityof3.5%.Thisreflectsthetypicalsalinityofseawater.Therewasnoagitationinthetankcontainingthisliquid.(c) Silty water was potable tap water (as above) with plastering sand and top soiladded(approximately3kgofeachin300lofwater). Thesandandsoilwerekeptinsuspensionbyagitatingthewaterwitharecirculatingpump.Thepumpwasswitchedonfor4hrsandofffor2hrsthroughoutthedurationofimmersionofsamples.Environmentalconditions:Opaqueblackplastictankseachcontainingapproximately300lofwaterwerekeptforthedurationofthetestingintheBASEClaboratorywarehouse,adjacenttotheinsulationresistance/voltagetestarea.Thetemperatureinthewarehouseareawasloggedandwasrecordedduringthetesting.Theaverageairtemperatureduringtheperiodofinitialtesting(OctobertoDecember2014)was18.7°C,withamaximumof24.9°Candaminimumof12.6°C,withdiurnalvariation.Theaverageairtemperatureduringtheperiodoffollow-uptestingforprotocol5(AugusttoNovember2015)was23°C,withamaximumof27°Candaminimumof18°C,withdiurnalvariation.Theaveragerelativehumidityinthelaboratoryareaduringthisperiodwas48%RH,withamaximumof58%RHandaminimumof37%RH.Atmosphericpressurevariedbetween985mBarand1010mBar,withanaverageof998mBar.PhotographsofthearrangementsandcableconditionsaftertestareincludedinAnnexB.

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4. ResultsofTestsThedetailedresultsoftheindividualtestsandexaminationsforeachoftheprotocolscarriedoutaredetailedintheAnnex.Thefollowingaretabulatedsummariesoftheresults.Protocol1-Wicking:2msampleverticaldip,20cmimmersedfor1weekatroomtemperatureResultsshowwaterpenetrationincm A

6491X1x1.5mm2

Solid

B6491X

1x2.5mm2Solid

C6491X

1x4.0mm2Stranded

D6242Y

2x2.5mm2Solid

E6242Y

2x2.5mm2Stranded

F6242B

2x2.5mm2Solid

Cleanwater 0 0 0 8 32 2Saltywater 0 0 2 2 30 2Siltywater 0 0 0 10 8 0 Protocol2-Penetration:4mcoilofsampleimmersedin1mwaterwith1mofsampleoutofwaterfor1weekatroomtemperatureResultsshowwaterpenetrationincm A

6491X1x1.5mm2

Solid

B6491X

1x2.5mm2Solid

C6491X

1x4.0mm2Stranded

D6242Y

2x2.5mm2Solid

E6242Y

2x2.5mm2Stranded

F6242B

2x2.5mm2Solid

Cleanwater 0 0 500 10 300 0Saltywater 0 0 500 410 190 0Siltywater 0 0 500 340 340 0

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Protocol3–InsulationResistanceonDrying:2msampleverticaldip,1mimmersedfor24hrsatroomtemperature.Timesareafterremovalfromsolution.Resultsshowinsulationresistance. A

6491X1x1.5mm2

Solid

B6491X

1x2.5mm2Solid

C6491X

1x4.0mm2Stranded

D6242Y

2x2.5mm2Solid

E6242Y

2x2.5mm2Stranded

F6242B

2x2.5mm2Solid

Cleanwater Beforetest - - - 70GΩ 80GΩ >100GΩ15min. - - - 35GΩ 60GΩ >100GΩ30min. - - - 35GΩ 60GΩ >100GΩ45min. - - - 35GΩ 60GΩ >100GΩ4hr - - - 20GΩ 50GΩ >100GΩ24hr - - - 35GΩ 50GΩ >100GΩ48hr - - - 30GΩ 35GΩ >100GΩ1week - - - 30GΩ 50GΩ >100GΩ Saltywater Beforetest - - - 40GΩ 90GΩ >100GΩ15min. - - - 28GΩ 125MΩ 1.06GΩ30min. - - - 29GΩ 256MΩ 18.5GΩ45min. - - - 30GΩ 1.97GΩ >100GΩ4hr - - - 35GΩ 50GΩ >100GΩ24hr - - - 35GΩ 70GΩ >100GΩ48hr - - - 30GΩ 60GΩ >100GΩ1week - - - 35GΩ 60GΩ >100GΩ Siltywater Beforetest - - - 50GΩ 100GΩ >100GΩ15min. - - - 35GΩ 19.5GΩ 45GΩ30min. - - - 30GΩ 25GΩ >100GΩ45min. - - - 30GΩ 35GΩ >100GΩ4hr - - - 35GΩ 60GΩ >100GΩ24hr - - - 40GΩ 70GΩ >100GΩ48hr - - - 40GΩ 60GΩ >100GΩ1week - - - 30GΩ 60GΩ >100GΩ

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Protocol4–MediumTermImmersionInsulationResistance:5msamplesimmersedto1mwithendsclearofsolution,for3months,atroomtemperature.Timesarefromthestartofimmersion.ResultsshowinsulationresistanceandresultofHVtest A

6491X1x1.5mm2

Solid

B6491X

1x2.5mm2Solid

C6491X

1x4.0mm2Stranded

D6242Y

2x2.5mm2Solid

E6242Y

2x2.5mm2Stranded

F6242B

2x2.5mm2Solid

Cleanwater Before,HV - - - - Pass PassBefore,IR 12.6GΩ >100GΩ1week,HV - - - - Pass Pass1weekIR - - - - 9.96GΩ >100GΩ2weeks,HV - - - - Pass Pass2weeksIR - - - - 4.7GΩ >100GΩ1month,HV - - - - Pass Pass1monthIR - - - - 4.3GΩ >100GΩ3month,HV - - - - Pass Pass3month,IR - - - - 4.1GΩ >100GΩ Saltywater Before,HV - - - - Pass PassBefore,IR 7.1GΩ >100GΩ1week,HV - - - - Pass Pass1weekIR - - - - 2.97GΩ >100GΩ2weeks,HV - - - - Pass Pass2weeksIR - - - - 2.43GΩ >100GΩ1month,HV - - - - Pass Pass1monthIR - - - - 1.43GΩ >100GΩ3month,HV - - - - Pass Pass3month,IR - - - - 1.3GΩ >100GΩ Siltywater Before,HV - - - - Pass PassBefore,IR 4.6GΩ >100GΩ1week,HV - - - - Pass Pass1weekIR - - - - 1.95GΩ >100GΩ2weeks,HV - - - - Pass Pass2weeksIR - - - - 1.43GΩ >100GΩ1month,HV - - - - Pass Pass1monthIR - - - - 1.29GΩ >100GΩ3month,HV - - - - Pass Pass3month,IR - - - - 1.11GΩ >100GΩ

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Protocol5–ModelFlood,InsulationResistanceonDryingProtocol5–ModelFlood,InsulationResistanceonDrying:5msamplesimmersedto1mwithendsimmersedatdepth,for1week,atroomtemperature.Timesarefromthestartofdrying.Resultsshowinsulationresistancebrown-CPCandblue-CPC. D

6242Y2x2.5mm2

SolidL-CPC

D6242Y

2x2.5mm2Solid

N-CPC

E6242Y

2x2.5mm2StrandedL-CPC

E6242Y

2x2.5mm2StrandedN-CPC

F6242B

2x2.5mm2SolidL-CPC

F6242B

2x2.5mm2Solid

N-CPCCleanwater Pre-test 6.2GΩ 8.6GΩ 60GΩ 60GΩ >100GΩ >100GΩPost-test 1.71GΩ 1.93GΩ 26GΩ 30GΩ >100GΩ >100GΩ24hrs 928MΩ 1.10GΩ 19GΩ 22GΩ >100GΩ >100GΩ48hrs 829MΩ 969MΩ 17.5GΩ 20GΩ >100GΩ >100GΩ72hrs 871MΩ 1.17GΩ 18GΩ 21GΩ >100GΩ >100GΩ1week 1.04GΩ 1.16GΩ 21GΩ 23GΩ >100GΩ >100GΩ2weeks 1.18GΩ 1.27GΩ 24GΩ 26GΩ >100GΩ >100GΩ3weeks 1.30GΩ 1.37GΩ 28GΩ 29GΩ >100GΩ >100GΩ1month 1.18GΩ 1.25GΩ 27GΩ 30GΩ >100GΩ >100GΩ2months 361MΩ 457MΩ 40GΩ 40GΩ >100GΩ >100GΩ3months 249MΩ 351MΩ 60GΩ 70GΩ >100GΩ >100GΩ Saltywater Pre-test 6.7GΩ 8.4GΩ 60GΩ 70GΩ >100GΩ >100GΩPost-test 1.10GΩ 629MΩ 50.2MΩ 316MΩ 76GΩ 2.86GΩ24hrs 854MΩ 53.8MΩ 110MΩ 366MΩ >100GΩ >100GΩ48hrs 736MΩ 149MΩ 204MΩ 508MΩ >100GΩ >100GΩ72hrs 781MΩ 158MΩ 744MΩ 439MΩ >100GΩ >100GΩ1week 911MΩ 727MΩ 1.47GΩ 12.5GΩ >100GΩ >100GΩ2weeks 1.03GΩ 998MΩ 4.9GΩ 22GΩ >100GΩ >100GΩ3weeks 1.08GΩ 1.10GΩ 1.61GΩ 23GΩ >100GΩ >100GΩ1month 939MΩ 1.01GΩ 789MΩ 26GΩ >100GΩ >100GΩ2months 274MΩ 339MΩ 355MΩ 35GΩ >100GΩ >100GΩ3months 206MΩ 261MΩ 1.20GΩ 50GΩ >100GΩ >100GΩ Siltywater Pre-test 6.6GΩ 8.7GΩ 70GΩ 70GΩ >100GΩ >100GΩPost-test 2.39GΩ 2.61GΩ 35GΩ 22.5GΩ >100GΩ >100GΩ24hrs 1.01GΩ 1.13GΩ 25GΩ 5.36GΩ >100GΩ >100GΩ48hrs 841MΩ 934MΩ 22GΩ 4.96GΩ >100GΩ >100GΩ72hrs 874MΩ 962MΩ 23GΩ 15GΩ >100GΩ >100GΩ1week 956MΩ 1.04GΩ 22GΩ 19.5GΩ >100GΩ >100GΩ2weeks 1.07GΩ 1.15GΩ 24GΩ 24GΩ >100GΩ >100GΩ3weeks 1.12GΩ 1.19GΩ 27GΩ 25GΩ >100GΩ >100GΩ1month 1.02GΩ 1.09GΩ 27GΩ 24GΩ >100GΩ >100GΩ2months 398MΩ 402MΩ 35GΩ 30GΩ >100GΩ >100GΩ3months 170MΩ 222MΩ 50GΩ 50GΩ >100GΩ >100GΩ

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Note:thedifferencesinbaselineIRvaluesbetweencablesDandEareattributabletodifferentpolymerblendsusedbydifferentmanufacturers(thesecableswerefromtwodifferentmanufacturers).

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5. FindingsandDiscussionFindings:Protocol1-Wicking:Wickingofwaterupthecablesabovethesurfacelevelwasfoundtooccursignificantlyonlywithsmallerstrandedconductors.Penetrationintoothercableswasminimal.Protocol2-Penetration:PenetrationofsubmergedcableendswasnotobservedforsolidsinglecorecableorLSHFtwinandearth,butdidoccurextensivelywiththestrandedconductorcablesandwithsolidPVCtwinandearth.Protocol3–InsulationResistanceonDrying:InsulationresistanceofimmersedandremovedsheathedcableswasnotaffectedwithsolidPVCtwinandearthbutshorttermreductionswereseenwithstrandedPVCandsolidLSHFcables.Allreadingsrecoveredtohighlevelswithinonehourofremovalfromwater.Atnotimedidtheinsulationresistancereadings(fortheshortlengthofcablemeasured)fallneartoWiringRegulationsconcernlevels.Protocol4–MediumTermImmersionInsulationResistance:Novoltagetestbreakdownswereobservedduringtesting.InsulationresistanceswereseentofallsteadilyovertimeforthePVCtwinandearth,butremainedhigherthanthemeasurementlimitfortheLSHFcableatalltimes.Atnotimedidtheinsulationresistancereadings(fortheshortlengthofcablemeasured)fallneartoWiringRegulationsconcernlevels.Afterthreemonthsinliquidthecablesinsaltyandsiltywaterweresomewhatdiscoloured,butdespitethistheelectricalperformanceremainedsatisfactory.

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Protocol5–ModelFlood,InsulationResistanceonDryingTherewasnoobservabledifferentintheconditionofthecablesafterimmersionfromtheProtocol4case.Thecablesalltestedacceptablyoneachoccasionwheretheyweretested.TherewasadifferenceinbaselineinsulationresistancebetweentheDandEsamplesattributabletodifferencesinpolymerandmanufacturer.TheinsulationresistancereadingsweretakenbetweeneachconductorandtheuninsulatedCPC,andhencewasprobingtheelectricalpropertiesoftheinsulationmaterialintheregionwhereitisincloseproximitytotheCPC.Thelowsmokehalogenfreetype(6242B)(F)wasobservedimmediatelypost-immersioninthesaltywatertoshowreducedinsulationresistanceforbothcores,butthesereadingsrecoveredwithin24hours,to‘offscale’.Allotherreadingsforthiscablefromtheothertwoimmersionliquids,andatallothertimesforthesaltywater,were‘offscale’.Thiscablethereforedemonstratedconsiderableresiliencetothemodelflood,withrapidrecovery.Oncompletionofthereadingsthecablewasslitandexaminedinternally.TheCPCwasdiscoloured(blackishdeposit)whereincontactwithsalty/siltywater–waterappearedtohavepenetratedalongtheCPCwithinthesheath.Therewasnopenetrationbywateralongtheconductorinthetwocores,betweenthecopperandtheXLPEinsulation.ForthetwoPVCtypes(6242Y)(DandE)theinsulationresistancereadingsdroppedafterremovalfromtheimmersionliquids,andthencontinuedtodropforafewdaysafterwards,onlythenbeginningtoslowlyrecover.Thesaltywaterproducedthelargestdecreasesininsulationresistance;cleanandsiltywaterresultedinsimilarbehaviours.BytheendofthemeasurementperiodsampleDhadnotfullyrecoveredcompletelytoitsoriginallevelofinsulationresistance,suggestingthattherecouldbealonger-termeffectonthespecificPVCinsulationmaterialused,notseenwiththeLSHFmaterialofsampleForthePVCmaterialofsampleE.ThefinalreadingsforsampleDappearedtobecontinuingtofallevenattheendofthemeasurementperiod.Thissuggeststhattheimmersioncouldhaveintroducedalong-termchangeinthepropertiesofthePVCinsulationofthisparticularmanufacturer’scable.

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TheothersampleofPVCcable(E)hadinmostcasesrecoveredtonearpre-testinsulationresistancereadingsbyonemonth,andthesecontinuedtoimprove.Onlythesaltywatercasedifferedforthiscable.ThissuggeststhatthePVCinsulationusedbythismanufacturerwasmoreresilienttoimmersionandthatoncedriedoutitreturnedtoitspre-teststate.ItshouldbenotedthatthemorevariablePVCcable(D)hadlowerinitialinsulationresistancevalues(6GΩto9GΩ)thanthemoreresilientone(E)(60GΩto70GΩ).Oncetestinghadbeencompletedthecableswereslitforinternalexamination.BothcablesshowedfullpenetrationofwateralongtheCPC(asevidencedbydiscolourationoftheCPC).Thesolidconductorsample(D)showedpenetrationofaround300mm.Thestrandedconductorsample(E)showedextensivepenetrationwithinthecore,aswouldbeexpectedfromitsmoreopenconductorconstruction.AtallstagesthemeasuredinsulationresistancesofallcablesfromallimmersionliquidswereacceptablefromaWiringRegulationspointofview,evenattheirlowestpoints.However,themeasuredlengthwasonly5mandnoaccessorieswerefitted.

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Discussion:Strandedconductorcablesappearsignificantlymorepronetoliquidpenetrationthansolidconductorcables.Thiscanberationalisedbecauseoftheairspacesbetweenstrandsoftheconductorinthecaseofastrandedconductor.Thereappearstobelowerpotentialforpenetrationupsolidconductorcables.Itmightbesuggestedthatinflood-proneinstallationsstrandedconductorsareavoided.Insulationresistancevalues(fortheshortlengthsofcablemeasured)didnotfallclosetoWiringRegulationsconcernlevels.Thissuggeststhattherewasinsignificantdegradationofthematerialsintheliquidsinvestigated,andthatfollowingsuitabledryingoutandsafetychecksthecablescouldbere-energisedwithlittleobservabledifferenceinperformance.However,somelong-termdifferencesinbaselineinsulationresistancecouldbeseenforoneofthePVCcables.Saltywaterappearedtobemoreproblematictorecoverfrom,withlowerinsulationresistancevaluesseenandvariabilitycontinuingovertime.Insulationresistancevaluesweremuchhigher,andrecoveryperiodsafterfloodingmuchshorter,forLSHFcablesthanforPVC.AcombinationofsolidconductorsandLSHFcables(6242B)appearedtohavethebestperformanceinthesetests.DifferenceswereapparentbetweenthePVCinsulationmaterialsusedbythetwodifferentmanufacturers.Onemanufacturer’scablerecoveredfromcleanorsiltywaterimmersionalmostcompletelytopre-testlevels,eventhoughitsconductorswerestranded,whereasanothermanufacturer’scablecontinuedtoexhibitmuchlowervaluesandon-goingvariability.Currentlythereisnostandardisedtestappliedtothesecablesduringmanufactureorforcertificationpurposeswhichwouldidentifysuchmaterialbehaviour.Itshouldbenotedthatthemeasurementswereconductedoverarelativelyshortperiodandnoassessmentofpotentialchangesinthelongevity(normalusagelifetimeof20+years)ofthecableswasattempted.NoissuesemergedfromthisworkthatmightsuggestareferraltotherelevantBritishStandardscommitteeforthesecables.

BASECInvestigationReportNoNAC069Issue2

Datetestingcommenced:01/10/14 Datetestingcompleted:27/11/15 Testedby:IMcGuinness

N/A=NotApplicable N/R=NotRequested N/T=NotTested

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PossibleRecommendationsforConsideration/Verification:Foranewinstallation/rewireinaflood-pronearea:

• ConsiderusingLSHFtypetwinandearthcablesratherthanPVCcables.• Usesolidconductorratherthanstranded.• ConsiderthemeritsofnotusingacablewithanuninsulatedCPC.• WherePVCcablesareused,useacablewithhighinitialinsulationresistance.

Incaseofaflood:

• Testandmonitortheinsulationresistanceoffloodedcablesduringthedryingprocess,onceisolated,comparingthemwherepossibletotestsonnon-floodedcables(forexampleanisolatedlengthofidenticalcableinanupstairscircuit).

• LSHFcables(solidconductor)maydryoutandbere-usablewithinafewdays.• ThedryingoutofPVCcablesmaytakelongerandmaynotrecoverfully.• Iftheinsulationresistancevaluescontinuetobesignificantlylowerorarenot

improvingafter1week/1month,thenconsiderreplacement.6. SuggestionsforPossibleFurtherWorkInvestigationoftheeffectsofshortcircuitonenergisedcablesduringinundation.Surveyofdifferentmanufacturers’cablestodetermineiftherearedifferencesinperformanceasregardsrecoveryfromflooding.ThisshouldbeappliedtobothPVCandLSHFtypes.

BASECInvestigationReportNoNAC069Issue2

Datetestingcommenced:01/10/14 Datetestingcompleted:27/11/15 Testedby:IMcGuinness

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AnnexA–DetailsofTestsandExaminationsCableSamplesofTypeAProtocol1:

Cleanwater:Nowaterpenetrationnoted

Saltywater:Nowaterpenetrationnoted

Siltywater:NowaterpenetrationnotedProtocol2:

Cleanwater:Nowaterpenetrationnoted

Saltywater:Nowaterpenetrationnoted

Siltywater:NowaterpenetrationnotedCableSamplesofTypeBProtocol1:

Cleanwater:Nowaterpenetrationnoted

Saltywater:Nowaterpenetrationnoted

Siltywater:NowaterpenetrationnotedProtocol2:

Cleanwater:Nowaterpenetrationnoted

Saltywater:Nowaterpenetrationnoted

Siltywater:Nowaterpenetrationnoted

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CableSamplesofTypeCProtocol1:

Cleanwater:Nowaterpenetrationnoted

Saltywater:Waterpenetrationnotedat2cmfromendbutnotbeyond

Siltywater:NowaterpenetrationnotedProtocol2:

Cleanwater:Waterpenetrationnoteduptoandincluding500cmfromend

Saltywater:Waterpenetrationnoteduptoandincluding500cmfromend

Siltywater:Waterpenetrationnoteduptoandincluding500cmfromend

BASECInvestigationReportNoNAC069Issue2

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CableSamplesofTypeDProtocol1:

Cleanwater:Waterpenetrationnoteduptoandincluding8cmfromend

Saltywater:Waterpenetrationnotedat2cmfromendbutnotbeyond

Siltywater:Waterpenetrationnoteduptoandincluding10cmfromendProtocol2:

Cleanwater:Waterpenetrationnoteduptoandincluding10cmfromend

Saltywater:Waterpenetrationnoteduptoandincluding410cmfromend

Siltywater:Waterpenetrationnoteduptoandincluding340cmfromendProtocol3:

Start 15min 30min 45min 4hrs 24hrs 48hrs 1week

Cleanwater: 70GΩ 35GΩ 35GΩ 35GΩ 20GΩ 35GΩ 30GΩ 30GΩ

Saltywater: 40GΩ 28GΩ 29GΩ 30GΩ 35GΩ 35GΩ 30GΩ 35GΩ

Siltywater: 50GΩ 35GΩ 30GΩ 30GΩ 35GΩ 40GΩ 40GΩ 30GΩ

Protocol5:

Pre-test Post-test 24hrs 48hrs 72hrs 1week 2weeks 3weeks

Cleanwater: 6.2GΩ 1.71GΩ 928MΩ 829MΩ 871MΩ 1.04GΩ 1.18GΩ 1.30GΩ

8.6GΩ 1.93GΩ 1.10GΩ 969MΩ 1.17GΩ 1.16GΩ 1.27GΩ 1.37GΩ

Saltywater: 6.7GΩ 1.10GΩ 854MΩ 736MΩ 781MΩ 911MΩ 1.03GΩ 1.08GΩ

8.4GΩ 629MΩ 54MΩ 149MΩ 158MΩ 727MΩ 998MΩ 1.10GΩ

Siltywater: 6.6GΩ 2.39GΩ 1.01GΩ 841MΩ 874MΩ 956MΩ 1.07GΩ 1.12GΩ

8.7GΩ 2.61GΩ 1.13GΩ 934MΩ 962MΩ 1.04GΩ 1.15GΩ 1.19GΩ

1month 2months 3months

Cleanwater: 1.18GΩ 361MΩ 249MΩ

1.25GΩ 457MΩ 351MΩ

Saltywater: 939MΩ 247MΩ 206MΩ

1.01GΩ 339MΩ 261MΩ

Siltywater: 1.02GΩ 398MΩ 170MΩ

1.09GΩ 402MΩ 222MΩ

BASECInvestigationReportNoNAC069Issue2

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CableSamplesofTypeEProtocol1:

Cleanwater:Waterpenetrationnoteduptoandincluding32cmfromend

Saltywater:Waterpenetrationnoteduptoandincluding30cmfromend

Siltywater:Waterpenetrationnoteduptoandincluding8cmfromendProtocol2:

Cleanwater:Waterpenetrationnoteduptoandincluding300cmfromend

Saltywater:Waterpenetrationnoteduptoandincluding190cmfromend

Siltywater:Waterpenetrationnoteduptoandincluding340cmfromendProtocol3: Start 15min 30min 45min 4hrs 24hrs 48hrs 1weekCleanwater: 80GΩ 60GΩ 60GΩ 60GΩ 50GΩ 50GΩ 35GΩ 50GΩSaltywater: 90GΩ 125MΩ 256MΩ 1.97GΩ 50GΩ 70GΩ 60GΩ 60GΩ

Siltywater: 100GΩ 19.5GΩ 25GΩ 35GΩ 60GΩ 70GΩ 60GΩ 60GΩ

Protocol4: Start 1week 2weeks 1month 3months IR HV IR HV IR HV IR HV IR HVCleanwater: 12.60GΩ Pass 9.96GΩ Pass 4.70GΩ Pass 4.30GΩ Pass 4.10GΩ Pass

Saltywater: 7.10GΩ Pass 2.97GΩ Pass 2.43GΩ Pass 1.43GΩ Pass 1.30GΩ Pass

Siltywater: 4.60GΩ Pass 1.95GΩ Pass 1.43GΩ Pass 1.29GΩ Pass 1.11GΩ Pass

BASECInvestigationReportNoNAC069Issue2

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Protocol5:

Pre-test Post-test 24hrs 48hrs 72hrs 1week 2weeks 3weeks

Cleanwater: 60GΩ 26GΩ 19GΩ 17.5GΩ 18GΩ 21GΩ 24GΩ 28GΩ

60GΩ 30GΩ 22GΩ 20GΩ 21GΩ 23GΩ 26GΩ 29GΩ

Saltywater: 60GΩ 50.2MΩ 110MΩ 204MΩ 744MΩ 1.47GΩ 4.9GΩ 1.61GΩ

70GΩ 316MΩ 366MΩ 508MΩ 439MΩ 12.5GΩ 22GΩ 23GΩ

Siltywater: 70GΩ 35GΩ 25GΩ 22GΩ 23GΩ 22GΩ 24GΩ 27GΩ

70GΩ 22.5GΩ 5.36GΩ 4.96GΩ 15GΩ 19.5GΩ 24GΩ 25GΩ

1month 2months 3months

Cleanwater: 27GΩ 40GΩ 60GΩ

30GΩ 40GΩ 70GΩ

Saltywater: 789MΩ 355MΩ 1.20GΩ

26GΩ 35GΩ 50GΩ

Siltywater: 27GΩ 35GΩ 50GΩ

24GΩ 30GΩ 50GΩ

BASECInvestigationReportNoNAC069Issue2

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CableSamplesofTypeF:6242B2x2.5sqmmSolidconductorProtocol1:

Cleanwater:Waterpenetrationnotedat2cmfromendbutnotbeyond

Saltywater:Waterpenetrationnotedat2cmfromendbutnotbeyond

Siltywater:NowaterpenetrationnotedProtocol2:

Cleanwater:Nowaterpenetrationnoted

Saltywater:Nowaterpenetrationnoted

Siltywater:NowaterpenetrationnotedProtocol3: Start 15min 30min 45min 4hrs 24hrs 48hrs 1week

Cleanwater: >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩSaltywater: >100GΩ 1.06GΩ 18.5GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩSiltywater: >100GΩ 45GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩProtocol4: Start 1week 2weeks 1month 3months IR HV IR HV IR HV IR HV IR HVCleanwater:

>100GΩ Pass >100GΩ Pass >100GΩ Pass >100GΩ Pass >100GΩ Pass

Saltywater:

>100GΩ Pass >100GΩ Pass >100GΩ Pass >100GΩ Pass >100GΩ Pass

Siltywater:

>100GΩ Pass >100GΩ Pass >100GΩ Pass >100GΩ Pass >100GΩ Pass

BASECInvestigationReportNoNAC069Issue2

Datetestingcommenced:01/10/14 Datetestingcompleted:27/11/15 Testedby:IMcGuinness

N/A=NotApplicable N/R=NotRequested N/T=NotTested

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Protocol5:

Pre-test Post-test 24hrs 48hrs 72hrs 1week 2weeks 3weeksCleanwater: >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩSaltywater: >100GΩ 76GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ 2.86GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩSiltywater: >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ

>100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ >100GΩ

1month 2months 3months

Cleanwater: >100GΩ >100GΩ >100GΩ

>100GΩ >100GΩ >100GΩ

Saltywater: >100GΩ >100GΩ >100GΩ

>100GΩ >100GΩ >100GΩ

Siltywater: >100GΩ >100GΩ >100GΩ

>100GΩ >100GΩ >100GΩ

BASECInvestigationReportNoNAC069Issue2

Datetestingcommenced:01/10/14 Datetestingcompleted:27/11/15 Testedby:IMcGuinness

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AnnexB–Photographs

Figure1:Arrangementoftanksandsuspensionofcables.

Figure2:Arrangementofcableendsdippedintotheliquid(Protocol1–Wicking).

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Figure3:ConditionofthecablesafterProtocol2-Penetration.

Figure4:ConditionofcablesafterProtocol4–MediumTermImmersionInsulationResistance.Lefttoright:silty,salty,clean.Greycables:PVC;whitecable:LSHF.

BASECInvestigationReportNoNAC069Issue2

Datetestingcommenced:01/10/14 Datetestingcompleted:27/11/15 Testedby:IMcGuinness

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Figure5:ConditionofcablesanddryingarrangementsafterProtocol5–ModelFlood,InsulationResistanceonDrying.Lefttoright:silty,salty,clean.Greycables:PVC;whitecable:LSHF.

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