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#DATUM PLANE PDF#
#DATUM PLANE CODE#
#DATUM PLANE CRACK#

To prevent this from happening, we use position tolerances as guidance for CNC turning and milling services. The cylinder cover is useless, and a different piece must be used. In the event that they don’t, the two parts will not mate, and the lubrication oil for the valve assembly will leak out, defeating the purpose of the cover. This is important for mating parts to ensure a seamless assembly.įor example, the screw holes on a cylinder head cover must match the screw holes on the engine casing in size as well as position. We use this concept in GD&T to control the variation of a specific feature from its desired position. It is more correctly referred to as “position”. True position is a GD&T callout for specifying the position of a feature. The goal of GD&T is to hold this variation within set limits. The actual size varies from the intended design. Fixed Docks (non-floating) in tidal or non-tidal locationsĪt fixed docks in locations subject to tidal fluctuations, the EDP is 2 feet (606 mm) above the local highest tide level (high water mark) that would occur under normal circumstances.We know that manufactured products can never match their theoretical drawings perfectly. For their inspection, the EDP is always a horizontal plane 30 inches (762 mm) above the water surface beside the dock. As long as dock floats don’t develop leaks and begin to sink, the decks of floating docks will maintain a constant distance above the water. Floating Docksįloating docks rest on floats and are anchored in place, meaning that they’re designed to have little or no lateral movement. The EDP will vary depending on whether the dock being inspected is: 1. Those inspecting homes along such rivers should be careful in identifying local conditions that may affect EDP. Maximum water heights may not be limited to tides or seasonal flow volume (or the combination of the two) but may be affected by tidal bores. The effect of tides on rivers can vary according to a number of factors. Shorelines closest to the coast will be most affected by tides and so will have shorter distances between changing EDP. In addition to coastal shorelines, shorelines that experience tidal fluctuations can include homes and residential developments on the shores of harbors, canals, and the near-coast portions of rivers. Storm surge influenced water levels can vary up to 15 feet (5 meters) from one end of Lake Erie to the other.įactors Affecting Highest Water Levels Tidal Shorelines For this reason, it’s important that they put forth their best effort in determining the most accurate EDP for the location of the properties they inspect. Radically different highest water levels can exist, sometimes within fairly short distances or within a single body of water. always a good idea! The EDP is covered in detail in in NEC 555.3 Electrical Plane Datum Distances Above EDP, electrical equipment can be installed and electrical connections can be made.Īlthough the NEC states that section 555 does not apply to private boat docks, the purpose of the EDP is to keep electrical equipment well above the water.

#DATUM PLANE CODE#

In relation to waterfront structures like docks, the National Electric Code (NEC) defines the Electrical Datum Plane (EDP) as a specified distance above the highest water level that will occur under normal circumstances. The Electrical Datum Plane (EDP) is a theoretical horizontal plane from which heights and depths can be measured.