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| Subject - service grounding | |
| bizex |
Hi guys,just got my first service upgrade job and i just wanted to make sure i got the grounding down pat,the existig service is 100amp and the customer wants to upgrade to 200amp,what i had planned to do was drive two 8 foot ground rods into the ground 4 feet apart bond them together then bond to the meter socket then back to the ground bar in the panel and also run supplemtary grond in raceway to the water meter the job is a private residence in MA any input you could give me i would appreciate....
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| JimmyDee | quote: 6' minimum spacing. Jim |
| lctrc789 | Jimmy is right never less then 6 ft apart for the augmented ground rods, as well as a water ground yes you have that part right. The meter base being tied to the the grounds is really more up to the local utility company... We have 3 power companies here, One requires you to ground the meter base to the system, the other does not require it at all and one does not want you to ground their equipment at all.. Remember to base your ground wire on your feeder size to the water meter for 200 amp service, and the ground rod conductor does not have to be larger then # 6 unless local jurisdiction says different. |
| bizex | Thanks for all of that i will be sure to check with the local utility to see if i need to bond to the meter base ,just one more question is there any reason i can't use 2 inch pvc conduit as the raceway for my feeders down to the meter base?.. again thanks for the info... |
| Ryan_J | quote: Are you asking about feeders or service lateral conductors? To answer your question, there is no problem using PVC. If it is subject to physical damage you will want schedule 80. To be honest, I think PVC is the best way to do it...plastic pipes just don't get energized and hurt people, ya know? |
| lctrc789 | Again, ask the local utility on what they require, some require 2 inch rigid here no exceptions, one allows nothing less than 2 1/2 inch PVC or rigid. Many of the local utilities have books they will give you to answer these questions. |
| bizex | Yes i was talking about the raceway for the feeders i,ll probably go with two and a half inch pvc but i,ll see if I can pick up some wriiten info from the utility again many thanks... |
| Ryan_J | Feeders are beyond the scope of a utility. You might want to take a look at the article 100 definitions. |
| blackrd | Also check with your AHJ, hes the one you have to worry about satisfying. |
| devo | I'm based in MA as well and wanted to remind you to hit the street side of water meter before you hit house side, also, 1 1/2" pvc is allowed for 3 2/0 THWN but, if using any LBs 1 1/2" won't take 3 2/0... just use 2" and give yourself some wiggle room...PS 2 1/2" is huge and would look funny on a residence |
| stedder | I agree w/ devo, 2 1/2 is huge and head is way out of place, the idea of using 2 0r 2 1/2 rigid may be intended for use as a guyed or self supporting mast service. (local utility usually does have guidelines for these) |
| lctrc789 | If we are talking underground the minimum here is 2 1/2 inch it is very common and has been for years... Overhead they allow 1 1/4 minimum unless the triplex is masted to it then 2 inch rigid is a minimum.. |
| stedder | seems like it'd be a real battle gettin' 200 amp service conductors in 1.25". "down to the meter base" makes me think its o/h. Here in NY we drive 8' grd rods 6' apart, bond to each other then to meter pan (#4 stranded, continuous), if there's no need for disconnect, we use seu to the panel, the neutral carries bond to the panel and then a water bond from the panel to cold water (#4 stranded again)if there is an exterior main disco then ser cable, or 4 wires in conduit (2 current carriers a fullsize insulated neutral and a ground)and seperate the gd and neu at the service panel. Unless a mast for height considerations is necessary surface strapped PVC is fine, 2" works. If there is a water meter or filter system they need to be jumpered W/ the water bond (not necessarily continuous) but a good idea if possible. |
| lucky1122 | bizex the water pipe electrode (in continuous contact for at least 10 feet with earth is the main electrode the driven rod is a supplementary electrode. one rod is required unless the resistance to ground is greater then 25 OHMS then an additional rod driven a minimum of 6 feet apart is required . Did you know that actually the distancing of rods would be more effecive at a slightly grater distance somewhere closer to 12 ft. It has something to do with the shells that theoretically exist between the rods. |