Electrical Safety of Street Light Systems.pdf

1952 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 26, NO. 3, JULY 2011

Electrical Safety of Street Light SystemsGiuseppe Parise, Fellow, IEEE, Luigi Martirano, Senior Member, IEEE, and Massimo Mitolo, Senior Member, IEEE

AbstractStreet light systems are publicly accessible electricalpieces of equipment out of the physical control of who operates/owns them. Street lighting systems typically include low-voltageloads, distributed in a large area, and are collectively protectedby the same device. Under fault conditions, hazardous potentialsmay appear on the metal enclosures of these systems, and exposepeople to shock hazards. To reduce the risk to an acceptable level,different solutions for the bonding and grounding are available.The Standard IEC 60364 and a current worldwide tendency seemto encourage the use of Class II equipment for the street light sys-tems. Class II components, such as the wiring systems, the lightfixtures, etc., have double or reinforced insulation. In this paper,these authors analyze technical alternatives to protect against in-direct contact in light of the IEC standards. In order to elevate thelevel of safety offered by Class II metal poles, the adoption of spe-cial circuitry and bonding connections to continuously monitor thedouble insulation of metal poles is proposed.

Index TermsEarth, exposed-conductive-parts, extra-neous-conductive-part, grounding electrode, light pole, neutralresidual current device, street lighting system, TI system, TNsystem, TT system.

I. INTRODUCTION

S TREET lighting systems are a typical case of distributedlow-voltage loads located in large areas, and collectivelyprotected by the same device. In most cases, lighting systems ofstreets, parkways, and other public areas are under the respon-sibility of electrical utilities. Utilities maintain and operate thesystem and ensure safe illumination during the hours of dark-ness (approximately 4000 h/yr).

Luminaries may be mounted on steel or wooden poles, fedwith underground cables, originating from the nearest avail-able distribution line. Typically in the U.S., the single-phase,three-wire, 120/240 V, or the three-phase, four-wire, 277/480 Vare adopted; in Europe, the single-phase, two-wire, 230 V, orthe three-phase, four-wire, 400/230 V distribution systems aretypical.

Technical standards of the International ElectrotechnicalCommission (IEC) specify the use of Class II equipment for thestreet light systems as the protection against indirect contact.Class II components, such as the wiring systems, the lightfixtures, etc., have a double or reinforced insulation. In normaloperating conditions and for properly maintained systems,

Manuscript received October 21, 2010; revised February 16, 2011; acceptedMarch 15, 2011. Date of publication April 29, 2011; date of current version June24, 2011. Paper no. TPWRD-00806-2010

G. Parise and L. Martirano are with the Department of Electrical Engineering,University La Sapienza, Rome 00184, Italy (e-mail: [email protected]; [email protected]).

M. Mitolo is with the Electrical Department of Chu and Gassman, New York,NY 08846 USA (e-mail: [email protected]).

Color versions of one or more of the figures in this paper are available onlineat http://ieeexplore.ieee.org.

Digital Object Identifier 10.1109/TPWRD.2011.2131690

TABLE IGROUNDING SYSTEMS ACRONYMS DEFINED BY IEC.

the risk of breakdown of both layers of insulation is deemedextremely low.

However, double insulation of Class II components of streetlighting systems may actually fail during their life-cycle. Thismay be caused by lack of maintenance due to their possible largeextension, as well as by their critical operating conditions, suchas, for example, car impacts or animal intrusions into poles. Asa consequence, the loss of the double insulation of componentswithin metal poles, which may go undetected if the leakage cur-rent is below the trip setting of protective overcurrent devices,exposes people to the risk of electric shock.

In this paper, the authors discuss possible alternatives for theprotection against indirect contact in light of the aforementionedIEC standards. In addition, to increase the level of safety offeredby Class II metal poles in different grounding systems, the au-thors propose the adoption of special circuitry and bonding con-nections to monitor continuously the status of their double in-sulation. Throughout the entire paper, the terms ground andearth are used as synonyms.

II. PROTECTION AGAINST INDIRECT CONTACTAND TYPES OF GROUNDING SYSTEMS

In low-voltage (LV) systems, the protection against indirectcontact may be achieved by automatic disconnection of thesupply. This measure calls for the grounding of the neutral ofthe LV supply, as well as of the enclosures of equipment, alsoreferred to as exposed conductive parts (ECPs). This groundingis preferably carried out through an earthing electrode commonto source and loads (i.e., the TN system), but can also beachieved through two independent grounding systems (i.e.,the TT system). To further clarify the differences among theTT, TN, and IT grounding systems, explanatory figures areprovided in the Appendix.

The different types of grounding systems are codified by IEC60364 through the XY-Z acronyms (Table I). This codification

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PARISE et al.: ELECTRICAL SAFETY OF STREET LIGHT SYSTEMS 1953

Fig. 1. TN-S system: protective conductors (PE) are connected to the power-supply ground electrode.

allows the introduction of the TI grounding system, which is notformally defined in IEC standards.

In the XY-Z acronym: the X-letter describes the condition of the neutral point of

the grounding of power-supply global positioning system(GPS) with respect to ground:

direct connection of source neutral to earth;neutral is ungrounded, or grounded through animpedance.

The Y-letter describes the condition of the exposed con-ductive parts (ECPs) with respect to ground:

connection of the ECPs to ground, independentof the GPS;connection of the ECPs to GPS;ECPs are not connected to GPS.

The Z-letter (if any) describes the arrangement of neutraland protective conductors (PE):

neutral wire and PE are separated;neutral wire and PE are combined in a singleconductor (PEN).

Based on the previous text, the TI grounding system is charac-terized by grounded power supplies and by ungrounded metalenclosures of equipment.

Low-voltage loads are usually supplied by radial distribu-tion systems. A basic solution is the TN system, where all ofthe simultaneously accessible ECPs must be connected to thegrounding of the power supply via protective conductors. TheTN-S is a practical solution when the LV loads are concentratedin the same area as the MV/LV substation (Fig. 1).

In TN-S systems, the three-phase distribution line consists offive-wire (H-H-H-N-PE), whereas the single-phase distributionline consists of three-wire (H-N-PE). In both cases, the protec-tive conductor and neutral wire are distinct conductors (Fig. 1).

Extraneous-conductive-parts (EXCPs) must also be bondedto the main earthing terminal of the building, as close as possibleto their point of entry within it. EXCPs may include metallicparts of the building structure, metal pipe systems for gas, water,heating, and noninsulating floors and walls [8].

Note that in the IEC approach for LV power systems, theuse of the TN system is possible only if the user owns theMV/LV substation. In this case, the service entrance is suppliedby the utility at medium-voltage. Consequently, in residential

Fig. 2. (a) TT system with light poles collectively protected by the same FPDand (b) independently protected by local protective devices LPD.

or small commercial applications, powered by utility-ownedtransformers, only the TT system can be implemented.

Where street lighting systems are in areas where it may notbe possible, or practical, to implement either the TT or the TNsystem, the adoption of Class II components for all the elementsof the lighting system (e.g., poles, light fixtures, cables, splices,terminal strips, etc.) is an alternative approach. Class II compo-nents have double, or reinforced, insulation: protections againstdirect contact (also referred to as basic protection) and againstindirect contact (also referred to as fault protection) are, respec-tively, provided by the basic and the supplementary insulations.

Reference [1] defines as Class II, the metal poles whose hand-hole cover on the lighting column is separated from wires byinsulating material (e.g., sleeves or tubes).

In this case, [1] does not require the intentional earthing of theconductive parts of the lighting column; thus, protective conduc-tors are not provided in the electrical distribution system.1

III. TT STREET LIGHTING SYSTEM

In low-voltage TT systems (generally used in Europe) thedistribution line is carried out through four-wire (H-H-H-N)or two-wire (H-N for single-phase loads) systems, generally at400/230 V (or 380/220 V), and at 50 Hz.

At the service panel, a protective conductor (PE) is locallyearthed, and kept separate from the neutral wire. Downstreamthe service panel, the local distribution system consists of a five-wire system (H-H-H-N-PE for three-phase loads) or a three-wire system (H-N-PE for single-phase loads).

For TT systems, all ECPs collectively protected by the samefeeder protective device (FPD) must be connected to a commonearth electrode [3]. However, if in addition to the FPD, localprotective devices (LPDs) are used for each pole or group ofpoles, independent grounding systems may be allowed (Fig. 2).

1The absence of equipment grounding conductors in particular cases, such asdouble-insulated appliances, is a concept also present in [2] (Art. 250.114 Ex),adopted in the U.S.


Fig. 3. TN-C-S systems: the PEN conductor acts as a grounded conductor andas an equipment grounding conductor.

In the TT system, ground-fault currents are greatly limited bythe earth resistance of the earth electrodes; the fault loop alsoincludes the earth resistance of the utility substation. Thus, aprotective overcurrent device may not trip within the maximumpermissible times [5], since the magnitude of the ground-faultcurrent might be below the threshold of its long time pickup.Thus, in TT systems, residual current devices (RCD) must nec-essarily be employed. In the TT system of Fig. 2, protectionagainst indirect contact is achieved by using RCD at a level of:

FPD in case of a common earth electrode [Fig. 2(a)]; LPD in case of independent earth electrodes; in this case,

FPD may have a delayed instantaneous tripping time (nohigher than 1 s) [Fig. 2(b)].

IV. TN-C-S STREET LIGHTING SYSTEM

In low-voltage TN-C-S systems (generally used in NorthAmerica), the distribution line is carried out through a four-wire(H-H-H-PEN) three-phase, or three-wire (H-H-PEN), doublesingle phase. In these systems, the PEN conductor acts as agrounded conductor and a PE (Fig. 3).

The system becomes a TN-S system downstream the userpanel, where a separate protective conductor PE originates. At-tention is drawn to the fact that in the TN-S portion of TN-C-Ssystems, the PE must not pass through the RCDs toroid, so thatfault currents will not circulate through it and possibly desensi-tize it, invalidating its protection.

V. TI STREET LIGHTING SYSTEM INTEGRATED WITH ARESPONSIBLE MAINTENANCE

In TI systems (generally used for street lighting system inItaly), the electrical distribution line consists of a four-wire(H-H-H-N) three-phase, or two-wire (H-N) single-phasesystem. The neutral point of the source is grounded, whereas allof the electrical components are Class II, and are ungrounded(Fig. 4). In this case, the FPD may be an overcurrent protec-tive device. Each electrical component of the TI system mustguarantee the double insulation, not only by construction,but also by installation. Steel poles supported by concreteplinths have an optimal mechanical resistance against naturalevents (e.g., high winds, thunderstorms, ice accumulation, etc.)and accidental events (e.g., car impacts). Let us note that ina TI system, each component, such as switchgears, cables,luminaries, terminations, joints (straights and 90 ), etc, must

Fig. 4. In TI systems, the neutral point is grounded and the poles (potentialECPs) are Class II.

Fig. 5. Cast polyurethane resin splice for Class II, multicore plasticinsulated cables.

guarantee double insulation characteristics (Class II), bothby construction, as shown in datasheets, and by installation(adopting special requirements).

It is, in fact, important that the installation of Class II equip-ment (especially branch joints and connections) should notcompromise the protection prescribed in the specifications fordouble insulated equipment.

For example, the installation of Class II, multicore, plasticinsulated cable splices, used to derive the branch circuit in thehandhole at the pole, requires special materials and techniques(Fig. 5).

For the street light electric distribution systems, IEC stan-dards promote the TI system, which does not call for the RCDs;this solution avoids nuisance tripping that could determine un-safe conditions especially in areas at high vehicular traffic.

The disadvantage of this arrangement is that if the doubleinsulation fails, the TI system degrades to a TT system; there-fore, overcurrent protective devices may not clear the fault forthe reasons examined in Section III. Thus, in this case, mainte-nance implies a higher responsibility for the owner of the streetlighting system.

If, for instance, the double insulation of the luminaire termi-nals fails due to, for example, an incorrect lamp replacement(Fig. 6), the surface of the metal pole may become permanentlyenergized, exposing people to the risk of electric shock, until amaintenance crew detects the failure.

Actual earth measurements carried out in TI systems showthat a 10 m steel pole, whose foundation plinth is embedded inthe ground for 0.8 m (Fig. 7), offers relatively high values ofresistance-to-ground. If, for example the pole earth resistanceassumes a value of , in TI street lighting systems supplied


Fig. 6. Luminaire terminations with faulty double insulation.

Fig. 7. Typical street light pole.

at 400/230 V, the earth fault current caused by the faulty doubleinsulation will not exceed 11 A.

The metal pole can assume almost the whole supply value of230 V, which is permitted for no more than 0.2 s. The groundcurrent may be even lower, if we consider the limitation ef-fect caused by the arc impedance. Arc faults to ground, in fact,are more likely to occur than bolted faults in ac low-voltagesystems.

Consequently, it would be advisable to implement a mainte-nance program to:

periodically inspect the publicly exposed lighting systemto confirm the absence of damages to the structures;

periodically test the insulation between live conductors andearth, as per the conceptual diagram presented in Fig. 8.

The insulation-to-ground of the system will pass the test ifupon the application of a voltage of 500 V for 60 s, the resistancemeasured is greater than:

, if the test is conducted with all the luminariesdisconnected (very unpractical);

, if the test is arranged with all the lumi-naries connected; where L is the length in kilometers of

Fig. 8. Conceptual representation of the ground insulation test for single-phasecircuits supplying poles.

Fig. 9. Feeder within the panelboard is disconnected from the CB for the insu-lation-to-ground test.

the line, with a minimum of 1 km, and N is the number ofluminaries.

For example, for a system with an extension not exceeding1 km, which supplies 30 luminaries, the minimum value ofthe insulation resistance is about ; a leakage current ofabout 3.5 mA at 230 V corresponds to this value of insulationresistance.

Although conceptually simple, the aforementioned procedureis rather complex to perform, because the personnel must tem-porarily drive an auxiliary ground rod, not always an easy taskin urban areas, and disconnect the feeder within the panelboard(Fig. 9).

Attention is drawn on the fact that [1] states that metal struc-tures (such as fences, grids, etc.), which are in the proximityof the street lighting system, but do not form part of it, neednot be connected to the earth terminal of the installation. Thisrequirement applies to any outdoor lighting installation, regard-less of the type of grounding system adopted. Reference [1] does


Fig. 10. The grounding electrode only operates upon failure of the double insulation (TT system).

not clarify whther the aforementioned metal structures that areEXCPs constitute an exception and should be earthed.

VI. PRACTICE IN THE U.S

Reference [2], adopted in the U.S., prescribes that conduc-tive enclosures of light poles be connected to the facility groundsystem through an equipment ground conductor in the sameraceway as the line wires. However, not all light street systemsare installed per [2].

Outdoor lighting installations mounted by utilities are, infact, in compliance with [9], which does not require protectiveconductors to bond the conductive poles. In some systems,the safety of steel, or aluminum, poles is exclusively entrustedupon local ground rods connected to each pole, without anybonding connection to the source or to the other poles.

The resulting system is a TT, which may not necessarily haveits characteristic safety requirements, such as a very low earthresistance for the single electrodes and/or the RCDs. Thus, low-intensity ground faults might not be cleared at all, causing thepermanent presence of stray voltages on publicly exposed en-closures.

This earthing arrangement is unsafe and, in fact, is notpermitted by [1], as mentioned in Section III. Details on thesafety reasons behind this prohibition have been discussed in[5]. Modern systems use a three-wire, or four-wire distributionline, which does include a ground wire. The ground conductoris bonded to the metal pole. The earth electrode system isusually a ground rod, or a concrete-encased electrode obtainedby using the re-bars of the plinth of the pole, connected at theservice point.

The City of Los Angeles Street Lighting Guide, for example,states that overcurrent devices (i.e., fuses or circuit breakers)without ground-fault protection shall protect all street lightingsystems. When circuit breakers are used, the neutral wire shallonly be grounded at the service point, and an additional equip-ment ground conductor shall be employed to bond together all

steel components of the lighting system [7]. The aforementionedarrangement constitutes a TN-S system.

As a further example of good practice, we can consider the re-quirements of the Louisiana Highways Lighting Systems, whichprescribes that: an equipment grounding conductor shall be in-stalled with each new circuit and shall be connected to each newlight pole and fixture.

In New York City, the chronic problem of stray voltages ap-pearing on metal poles is being mitigated by installing noncon-ductive composite covers on utility service boxes, and intro-ducing isolation transformers [5] within the poles.

These transformers allow the galvanic separation of thelighting circuit from the earth, thereby preventing the circula-tion of currents, if the basic insulation of the circuit, or of othercomponents within the pole, fails.

In addition, the utility has also developed a mobile detec-tion vehicle (MDV) that can survey for stray voltages on metalpoles while driving down the streets. MDVs are used to con-duct annual surveys and prior to public events to enhance publicsafety.

VII. PROPOSED SOLUTIONSThe authors suggest two types of solutions, applicable in al-

ternative or combined, to improve the TI system:1) an additional level of protection extended to all the com-

ponents of the street light system;2) a smart solution localized within the panelboard.

A. TI System With an Additional Level of ProtectionConsidering the basic benefits for safety of the double insula-

tion, but also the difficulties in detecting its failure, the authorssuggest, as extra levels of protection (Fig. 10), the addition ofa residual current relay within the protective device and, one orboth, of the following:

employment of multiconductor cables with an integralprotective conductor to reduce the risk of its accidentaldisconnection;


Fig. 11. Panelboard equipped with the test switch and accessible ground testelectrode.

addition of a buried bare grounding wire to be connectedto each metal pole in TI systems.

The bare grounding wire will have a minimum cross-sectionalarea of and be buried at a minimum depth of 0.50 mbelow grade. This additional earth electrode will integrate thenatural electrode constituted by the plinth.

In this arrangement, the protection against indirect contact isguaranteed by two levels:

a first level consisting of double insulated components; a second level consisting of the disconnection of the supply,

or the activation of an alarm, in the case of failure of thedouble insulation.

B. Smartpanel with an Insulation Monitoring DeviceAs explained in Section V, although conceptually simple, the

maintenance in the TI system is rather complex, due to the prac-tical difficulties setting up the insulation test circuit.

To facilitate the testing procedure, and drastically reduceits costs, the authors propose the adoption of a smartpanelequipped with a special insulation monitoring device (IMD).

The special IMD is composed of:1) a permanent testing circuitry consisting of a double-insu-

lated test switch and a ground test electrode permanentlyinstalled in an inspection well (Fig. 11).The test switch has two positions: power and test, sep-arated by an open status. The power position allowsthe normal supply of the light fixtures. The test positionshorts together the live conductors, allowing the insulationtest.When the switch is in test position, the insulation tester(indicated as Mohm in Fig. 10) is connected to the live

TABLE IICOMPARISON AMONG THE DIFFERENT SMART SOLUTIONS

conductors and to the test electrode. Two connection ter-minals are available at the smartpanel to accept the insula-tion tester leads.

2) The insulation tester can be either enclosed in the panelor external and portable. If the Mohm is enclosed in thepanel, the insulation test can be performed on a daily basiswithout personnel involvement, thanks to a contactor thatautomatically turns the test switch in the test position. Ifthe Mohm is portable, the insulation test is manual and hasto be performed by maintenance personnel.

3) A transmitter system (e.g., GSM, GPRS, or power-linecommunication (PLC)), capable of sending the testing datato the maintenance center, allowing a continuous and cost-effective maintenance activity.The aforementioned solution adds extra cost to the utility,which is estimated in an additional expense not exceeding50% of the panelboard cost. However, this extra expendi-ture would drastically reduce maintenance activities andgreatly increases public safety.Note that the new generation of lighting smartpanels isalready equipped with transmitter interfaces, so that theadditional cost reduces to the test switch and the testelectrode.

C. Smartpanel with Residual Current Monitoring DeviceTo further increase the public safety, the smartpanel could be

equipped with a residual current monitoring device (RCMD).The RCMD consists in a residual current relay that can initiatea local alarm and send an automatic notification to the mainte-nance center, without disconnecting the supply to the lightingsystem. The RCMD should be protected against surges, andhave a residual threshold of not less than 500 mA, to preventnuisance trippings.

Table II shows a comparison among the different proposedsolutions by assuming the TI system as the reference.

VIII. CONCLUSIONIt has been substantiated that fault loops in streetlight sys-

tems depend on the grounding system employed. The strategy


Fig. 12. TT grounding system.

for the protection against indirect contact must therefore be ac-cordingly studied.

TT, TI, and TN systems have fault loops of a different nature,the first two comprise the actual earth, which makes the pro-tection against indirect contact by disconnection of the supplybased on overcurrent devices difficult.

The TI system is an efficient solution to protect people fromelectric shocks and to preserve the continuity of the service, es-pecially in areas at high pedestrian and/or vehicular circulation.In fact, the probability that the basic and the supplementary in-sulations are both punctured is very low, but not zero, if we con-sider the hundreds of thousands of metal poles present in largecities. However, forensic cases have been documented (Fig. 6),proving that this event has occurred.

To reduce this risk, the authors propose testing circuitry to beimplemented within the lighting system panelboard. This cir-cuitry, thanks to a test electrode, can check the leakage to groundof the double insulation and alert the maintenance personnelwell before the complete failure of the Class II pole. In addition,these authors also propose the adoption of grounding electrodesfor Class II light pole systems, beneficial in the case of the un-detected failure of the double insulation.

Studies to generalize the proposed solutions in the case ofconcrete or wooden poles as well as in the case of light systemsin high-resistivity soils will be carried out in the future.

APPENDIX

In TT grounding systems, two independent earthing systemsare called for: one for the source and one for the equipment(Fig. 12).

In TN grounding systems, the earthing electrode is commonto the source and the equipment (Fig. 13).

In IT grounding systems, the source is not earthed, or isearthed through a high impedance; the equipment is grounded(Fig. 14).

For further details, see [3] and [10, ch. 6, 7, and 9].

Fig. 13. TN grounding system.

Fig. 14. IT grounding system.

REFERENCES

[1] 1996-04, 1st Ed., Electrical Installations of Buildings, Part 7. Require-ments for Special Installations or LocationsSection714: ExternalLighting Installations, IEC 60364-7-714, 1996.

[2] ANSI/NFPA 70, National Electrical Code 2008.. Quincy, MA, Na-tional Fire Protection Assoc.

[3] G. Parise, A summary on the IEC protection against electric shock,IEEE Trans. Ind. Appl., vol. 34, no. 5, pp. 911922, Sep./Oct. 1998.

[4] M. Mitolo, Is it possible to calculate safety?, IEEE Ind. Appl. Mag.,vol. 15, no. 3, pp. 3135, May/Jun. 2009.

[5] Low-Voltage Electrical InstallationsPart 4-41: Protectionfor SafetyProtection Against Electric Shock, 2005, Ed.5, IEC60364-4-41, 2005.

[6] M. Mitolo, On outdoor lighting installations grounding systems, inProc. IEEE Ind. Appl. Soc. 41st Annu. Meeting, Conf. Rec., Tampa, Fl,Oct. 2006, vol. 5, pp. 22242229.

[7] Bureau of Street Lighting City of Los Angeles, Design Standard andGuidelines, May 2007.

[8] M. Mitolo, M. Tartaglia, and F. Freschi, To bond or not to bond: Thatis the question, IEEE Trans. Ind. Appl., vol. 47, no. 2, pp. 989995,Mar./Apr. 2011.

[9] Standard ANSI/IEEE C2-2007, National Safety Electrical Code,C2-2007, 2008.

[10] M. Mitolo, Electrical Safety of Low-Voltage Systems. New York: Mc-Graw-Hill, 2009.


Giuseppe Parise (M82-SM03F10) was born inLuzzi (Cosenza), Italy. He received the ElectricalEngineering degree from the University of Rome,Rome, Italy, in 1972.

He has been with the Department of Electrical En-gineering, University of Rome La Sapienza since1973 and is currently a Full Professor of ElectricalPower Systems. He has authored about 190 papersand two patents. Since 1975, he has been a Designerof Power Electrical Systems in Buildings Complexes,such as in Roma Sapienza University City and Engi-

neering Faculty, Polyclinic Umberto I, Italian Parliament, Campus BiomedicalResearch Center.

Prof. Parise received three Prize Paper Awards from the IEEE/IAS PowerSystems Department. Since 1983, he has been a member of Superior Council ofMinistry of Public Works. He is active in IEEE\IAS, Chair of IA Italy SectionChapter, Member at Large of Executive Board 2007-2010, and is past Presidentof AEIT Romes Section. He is Chair of Electrical Power Systems Researchersof Sapienza University. He has been a Registered Professional Engineer since1975.

Luigi Martirano (S98M02SM11) received theM.S. and Ph.D. degrees in electrical engineeringfrom the University of Rome, Italy, in 1998 and2002, respectively.

In 2000, he joined the Department of ElectricalEngineering, University of Rome La Sapienza.Currently, he is an Assistant Professor of BuildingAutomation and Energy Management at the En-gineering Faculty and of Lighting Systems at theArchitecture Faculty. He is the author or coauthor ofmore than 60 papers and a co-inventor of one inter-

national patent. His research activities cover power systems design, planning,safety, lightings, home and building automation, and energy management. Heis a senior member of the IEEE Industry Applications Society, of the ItalianAssociation of Electrical and Electronics Engineers (AEIT), and of the ItalianElectrical Commission (CEI) Technical Committees CT205 and SC311B. Heis a Registered Professional Engineer.

Massimo Mitolo (SM03) received the Ph.D. degreein electrical engineering from University of NaplesFederico II, Naples, Itraly, in 1990.

His field of research is in analysis and groundingof power systems. He is currently the AssistantElectrical Department Head at Chu & Gassman,New York. He has authored many journal papers,and the textbook Electrical Safety of Low-VoltageSystems.

Dr. Mitolo is very active within the IEEE IAS In-dustrial & Commercial Power Systems Department,

where he currently is the Chair of the Power Systems Engineering (PSE) Com-mittee, the Chair of the Power Systems Analysis Subcommittee, and the Chairof the Power Systems Grounding Subcommittee. He is also an Associate Editorof the PSE and ES Scholarone Manuscript. He is also the recipient of the Lu-cani Insigni Award in 2009, for merits achieved in the scientific field. He is aregistered Professional Engineer in Italy.

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Electrical Safety of Street Light Systems.pdf