Delphia 33 - Engine Safety and Anticorrosion

57/99
ANTICORROSIONPROTECTION
Pic Theflowofvoltaiccurrentasaneffectof
connectionoftwoearthingsystemsofboth
yachtsthroughPE shore
.1
on .
T
DC(12V)iAC(230V)
Therulesofthebiggestsailingtycoon,theUSA,demandthePEcabletobe
connectedtothemainearthingDCinstallationminuspole(seepic.1p.108).In
Europe,accordingtothecurrentstandardsforboatsconcerningthelowvoltage
electricinstallations(PN-ENISO10133)andalternatingcurrent(PN-ENISO10297),
thisisnotnecessary.Itisenoughtoinstalladifferentialcircuitbreakerorseparating
transformerinthemainACinstallationcircuit.Then,ACandDCinstallationdonot
havetobeconnectedtotheearthingsystemtogether.ThePRSrulesconcerningthe
classificationandbuildingofyachtsandmotorboatsinthechapterdescribingthe
requirementsforinstallationsandelectricappliancesofhigherthansafevoltage,say
atthesametimeaboutthenecessityofpermanentconnectionofeachmetalelements
(whichmaybeundervoltage)toearthingsystem.Incaseofcommonlyusedon
yachtsandboatstheenergydivisionsystemTN-S,itisrealizedbythemeansofPE
cablewhichisconnectedtoeachpowersocket.
Oneofthemainproblemswhichboatownersfaceiselectrochemical
corrosion. herearecountrieswheretherearemanymotorandsailingboatsdocking
inmarinasatthesametimeusingtheshorepower.Theresultofthismaybeagiant
link.Amongthefactorswhichhelpsindevelopmentofcorrosionprocessthereare
wanderingcurrentsfrom installationsandthefactthatnotall
installationsontheboatsorinmarinasworkproperly.
Itmaybeclaimedthatevenproperlyinstalledandnotmodifiedsimple
installationafterconnectiontoshorepowersupplybecomesaninvitationfor
complicatedcorrosionprocesseswhichmaybeharmfultotheboat.Findinga
solutionpreventingthecorrosonprocessandatthesaetimenotreducingthe
effectivenessofantielectricshockcrewprotectionisarealchallenge.
Thesimplestsolutionwhichispracticedonsomeboatsisdisconnectionof
thePEcable(protectioncable)fromtheearthingDCsystem.Doingthatyoucutoff
theconnectionofoneelementofthelinkwithearthingPEcableontheshore,andthe
wayforvoltaiccurrentcutoffaswell.Aftermooringtothequayandconnectingto
theshorepower,theprotectioncableoftheboatinstallationisconnectedtoits
equivalentontheshoreandprovideseffectiveantielectricshockprotection.
115/230V
AC