E&S Grounding Solutions is the premier electrical grounding, earthing, and electrical safety consulting firm and contributors to the McGraw-Hill book “Standard Handbook for Electrical Engineers” authoring chapter 24: “Grounding Systems” in the 16th Edition.
Our lead electrical engineer David Stokin is the author of McGraw-Hills NEC 2014 Grounding and Earthing Handbook
which fully discusses above-grade wiring issues and below-grade earthing issues related to electrical grounding in conjunction with Article 250 of the 2011 National Electrical Code.
Call today for a free consultation on your electrical grounding project
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Mike asks us: “Does my electrical grounding system need to be connected to my buildings fire sprinkler system?”
Thank you Mike for the great question. Yes, your building or structures fire sprinkler system must be bonded to the common grounding system in accordance with the National Electrical Code NEC 250.104, and 250.104(D)(1); the Lightning Protection Code NFPA 780 4.14; and the Fire Sprinkler Code NFPA 13 10.6.8.1. It is also required under NFPA 24 the code for the installation of private water service. Continue reading
The National Electrical Code (NEC) first introduced swimming pool grounding and bonding in the 1962 edition. In this edition, the code required that all metal objects, including: the steel rebar in concrete (support), metallic conduit, piping systems, pool reinforcing steel, light fixtures, ladders, diving boards and the like, shall be bonded together and grounded to a common ground. A minimum 14 AWG wire was required for this bonding. Continue reading
John asks us: One of my junior electricians lost the green bonding screw in an electrical cabinet we are installing. Can I use a regular silver machine screw to replace it?
Allistair asks us: If you Consider a 3.5m long sailing boat, the
sailing boat is made of fiberglass and has a 5m aluminium mast. The mast is
held in place by three steel wire side stays. A mainstay that runs from top of
the mast to the bow of the boat and two side-stays that run from top of the
mast to port and starboard side of the hull. The foot of the mast rest on a
wooden body of the boat, 1m from the bow. Is it safe to sail a sailing boat
during a thunderstorm? Comment on your answer. If you had to design lightning protection for the boat, how would you go about doing it?
Allastairasks us: A structure has two separate earth systems: a
safety earth and an electronics earth. The safety earth is connected to an
earth-mat located 100m away from the structure. The safety earth is locally
earthed. Is this a safe configuration, in terms of lightning safety? Explain
your answer. If it is a problem, propose a solution.
Jeffery asks us: When a residential service is replaced in areas without city water systems, plastic well water line, and ground rods are all that is available, does the requirement change for only a # 6 copper conductor to the rods, being it is now primary gounding electrode and not supllimental. ( say larger home 120/240V, 400(320) Amp?
Melissa tells us: I have two transformers next to an electrical building. A 13.8-4160 and a 4160-480. MV transformer is resistance grounded to 100A. LV is solidly grounded. My engineer is telling me I need a beefy grid around both and it should be modeled as a substation due to the fact a transformer winding may become shorted to the transformer enclosure creating a SLG fault. He says if that happens, 34.4kA will go into the ground and this will create harmful step and touch potentials in about a 100-150ft diameter around the transformer. I don’t know much about this sort of thing, but I know typically, a very simple ground system is put into place, and not one with many many rods and runs of conductor. Can you tell me, not knowing more details, if his argument holds water and I should consider his design? I am told the soil is moderately conductive. 3350 ohm-cm to 6250 ohm-cm.
Thank you for your question regarding Ground-Fault Circuit Interrupter (GFCI) outlets and water coolers, it is our pleasure to help.
The National Electrical Code (NEC) Article 422.51 and 422.52 are very clear on this subject, you must have GFCI protection for water coolers. In fact, machines manufactured after January 1, 2005 must have integrated GFCI protection inside the circuitry of the system (see NEC 422.51). Depending on how your local inspector interprets the code (see NEC 422.52), you may be required to provide a dedicated GFCI outlet, even if the cooler has integral GFCI protection. Continue reading
Thank you for your question regarding 50% ground bars, it is our pleasure to help.
Busways have two ground conductors. One is an actual additional copper or aluminum bus bar in the stack with the phase conductors inside the housing. The other is when the protective metal housing around the bus bars is bonded and used as a ground path. Continue reading
Thank you for your question regarding the welding of steel rebar, it is our pleasure to help.
Not all rebar can be welded, particularly with the exothermic welding process as it must be able to heat the surface of the metal rebar to the melting point in order to ensure adhesion. In general, only steel rebar that is “Grade W” can be welded. Continue reading