[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-663431-105":59,"doc-detail-663431-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","national-grid-specifications-for-one-line-diagrams","National Grid Specifications for One Line Diagrams","","National Grid specifications outlining what must be shown on one-line diagrams for single-phase services of 400A or greater and three-phase services of 200A or greater. Requirements cover conductor details, conduit counts and materials, main switch and fuse or breaker settings, and comprehensive metering information including self-contained and CT-rated locations. The guide also provides metering guidelines such as a No Jumper policy, hot vs. cold sequencing rules, socket and bypass requirements, and installation positioning for outdoor and indoor meters.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":30,"@type":76,"position":81},"https://docshare.wps.com/document/technology/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/national-grid-specifications-for-one-line-diagrams/663431/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/national-grid-specifications-for-one-line-diagrams/663431.png","ImageObject",300,407,{"name":92,"@type":93},"pop out","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-30","2026-10-28",true,{"@type":102,"interactionType":103,"userInteractionCount":19},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"Which services require a one-line diagram submittal according to these specifications?","Question",{"text":112,"@type":113},"Submit one-line diagrams for all single-phase services rated 400 amps or greater, and for all three-phase services rated 200 amps or greater.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"What must the metering section include on the one-line diagram?",{"text":117,"@type":113},"Include self-contained details (number of meters, ganged status, manual bypass, and conductor location for metered and unmetered), plus CT-rated information such as location, disconnecting location, conductor size/number entering and leaving the CT cabinet, and termination points.",{"name":119,"@type":110,"acceptedAnswer":120},"What does the document say about the “No Jumper” policy and how work should be coordinated?",{"text":121,"@type":113},"A “No Jumper” policy is in effect due to revenue and safety concerns. Coordination with the Municipal Inspector’s approval would help National Grid complete meter work without interruption; if coordination is not possible, the existing meter may be installed if compatible, and National Grid can remove locking devices promptly in most instances.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},663431,1793227708,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":29,"category_name":30,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":19,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":14,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":129,"read_time":24},962090760408,"https://ap-avatar.wpscdn.com/davatar_085a072bc5b1113ac321206ff7593b45","National Grid Specifications for One Line Diagrams  \nThe following information is for reference only and will help you assemble your one line diagram.  \nPlease be sure to detail your diagram as accurately as possible. Any inconsistencies could delay the overall design of your requested service.  \nThe One-Line diagram must indicate the following and should be submitted for all single-phase services, 400 amps or greater and for all 200 amp or greater three-phase services.  \n1. Number of conductors, size of conductors, insulation, copper or aluminum  \n2. Number of conduits, size and material  \n3. Size of main switch, fuse size and class used. If circuit breakers are used, indicate frame size in amperes and the trip setting tobe supplied and adjusted or fixed  \n4. Metering shall indicate the following:  \nSelf-contained  \n􀁸 Number of meters  \n􀁸 Ganged  \n􀁸 Manual bypass  \n􀁸 Metered and unmetered conductor location  \nC.T. Rated  \n􀁸 Location  \n􀁸 Disconnecting location  \n􀁸 Conductor size and number  \nentering C.T. cabinet  \n􀁸 Conductor size and number leaving  \nC.T. cabinet and their termination point  \n􀁸 C.T. compartments in the switchgear shall require a set of switchgear shop drawings  \nMetered location, inside, outside or padmounted.  \nBelow is an example of a one line diagram and a list of metering guidelines. The one line diagram is for a 400 amp 120/208 three phase service and is for reference only.  \nMETERING GUIDELINES  \n􀁸 Jumped Socket Policy:  \n- A “No Jumper” policy is in effect. This policy is due to revenue and safety concerns.  \n- Coordination of the completed work with the Municipal Inspector’s approval would enable National Grid to complete the necessary meter work to avoid interruption of power.  \n- If such coordination is not possible, the existing meter may be installed in the socket if compatible. National Grid will accommodate requests for removal of locking device promptly in most instances. Within 24 hours if not an emergency.  \n􀁸 General Metering Parameters:  \n- Self-contained installations are limited to service sizes less than or equal to 400amp service (320 amp rated meter socket) 120/240, 120/208 .  \n- Hot sequence (meter ahead of main disconnect) vs. Cold sequence (meter disconnect ahead of meter) . Hot sequence is typically the standard, however, the following exceptions require cold sequence: Locations with more than 6 meters, 277/480 and 600 volt self-contained installations, and underground networks.  \n- Multiple meter locations require socket ID marking by owner or electrical contractor before meter installation.  \n- Meter height required to be between 3-6 feet for outdoor installations. Indoor meters required to be between 2-6 feet.  \n- CT Cabinet will be supplied and installed by the customer according to the company’s specifications.  \n􀁸 Meter Socket Requirements:  \n- All sockets must be UL approved.  \n- Bypass socket (safety arc shield) installations are required for all Commercial and Industrial service installations, and Common areas or Owner’s meter. If in doubt, presume bypass required unless otherwise authorized by National Grid’s Metering supervisor.  \n- Bypass sockets 200 amps or above require locking jaws.  \n- Class 320 sockets must be UL approved.  \n- Single Phase 120/208 installations require a 5th terminal at 9 or 6 o’clock positions.","cbCaivhSsVtlUYxP","https://ap.wps.com/l/cbCaivhSsVtlUYxP","pdf",70078,"English","# One-Line Diagram Requirements\n## Conductor, Conduit, and Switching Details\n## Metering Requirements\n# Metering Guidelines\n## Jumped Socket (No Jumper) Policy\n## General Metering Parameters\n## Meter Socket Requirements","[{\"question\":\"Which services require a one-line diagram submittal according to these specifications?\",\"answer\":\"Submit one-line diagrams for all single-phase services rated 400 amps or greater, and for all three-phase services rated 200 amps or greater.\"},{\"question\":\"What must the metering section include on the one-line diagram?\",\"answer\":\"Include self-contained details (number of meters, ganged status, manual bypass, and conductor location for metered and unmetered), plus CT-rated information such as location, disconnecting location, conductor size/number entering and leaving the CT cabinet, and termination points.\"},{\"question\":\"What does the document say about the “No Jumper” policy and how work should be coordinated?\",\"answer\":\"A “No Jumper” policy is in effect due to revenue and safety concerns. Coordination with the Municipal Inspector’s approval would help National Grid complete meter work without interruption; if coordination is not possible, the existing meter may be installed if compatible, and National Grid can remove locking devices promptly in most instances.\"}]","National Grid Specifications for One Line Diagrams | PDF"]