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| Subject - Is my house a separately derived system? | |
| unsaint34 | I am confused with the definition of a separately derived system. As usual, my house is powered by a transformer on a power pole. The transformer is a isolated tranformer, right? Therefore, isn't my house a separately derived system? |
| Romex Racer | No. If you had a backup power system, that would be seperately derived. |
| Ryan_J | quote: It may or may not be...it would depend on your transfer equipment and wether or not the grounded (nuetral) conductor is switched. Unsaint: I would say no, your house is not seperatley derived as defined in the NEC, because the NEC doesn't really address the supply side transformer, unless you own it. If you owned the transformer, then yes, your house is probably seperatley derived. Note: Why is it that I can not spell seperatley??? 
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| unsaint34 | It's separately. Thanks for your answer here and for other posts,Ryan. About this question I posted... someone directed me to read the code definition of "service." The book said service includes all equipment and conductors that supply power to premise wiring, therefore even if the secondary side of the transformer was not electrically connected to the primary side, my house is still service supplied. |
| rabbitgun | Ryan, I had a secretary return a typed letter that I had drafted by hand. She looked at me and said "There is A RAT in separate"......... |
| Ryan_J | quote: LMAO! I typically get the "RAT" part in there, but then something bad happens at the end when I get to ley or ely. You'll also notice that I typically use the word typically...thats because I can't spell ussualy! It's funny, I like to think that I can write fairly well, but those two words just kill me 
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| lucky1122 | Unsaint , The key is not the transformer up on the pole ,its whether the system is derived from other than the service. Anything that comes into your house,or for that matter a building no matter how large from the power supplier, is service related Equipment . All the feeders and branch circuits which are related to that system are part of that system. When another system is required ,and such a system is seldom required in a house, but there are some instances where they may be present ,and if it is isolated from the Circuit of origin electrically then it may meet the requirements. lets use the generator analogy since thats something not to far fetched.the defining point that would make the generator separately derived is whether or not the neutral is solidly connected to the service neutral in the transfer equipment or whether its switched. If the neutral is switched, then it must be treated as a separately derived system and grounded to the electrode system. you probably can see the relationship between the neutral conductors of both systems as being the point that defines the system as being separately derived or not. |