Why is SER cable not listed in 310-16? Does it fall under the USE guidelines because of the temp rating.
How many amps is 2-2-2-4 SER rated for?
Hi Tony,
Yes SER falls under article 338. The "R" to my understanding means raceway, if you have more than 3 conductors. Table 310-15(b)(6) rate SER #2 copper for 125 amps and 100 amps for aluminum. Hope this helps.
Joe
Table 310.15(B)(6) Can only be used for 120/240-Volt, 3-Wire, Single-Phase Dwelling Services and Feeders.
As you are using 2-2-2-4 SER this would be 4 wire so you can not use this table.
You need to use 310.16 Type SE cable contains Types RHW, RHW–2, XHHW, XHHW–2, THWN, or THWN–2 conductors so you need to know which type you have to know which column to use.
Also you will need to know your terminal temperature ratings to know which column you can use.
You must use the lowest temperature rating of the wire and terminals.
So the rating of 2 AWG aluminum is 75 amps at 60C or 90 amps at 75C
As far as the "R" I have always told that means SE round, helpful info when ordering a wet location connector.
I am glad I'm not the only one a little confused. I am using it to feed a sub panel for a 3 ton heat pump rather than use 2 separate circuits for heat strips and compressor. Plus I need to mount a recptacle near the unit. So because of all this I think it falls under 310-16. So is this classified as a feeder or a branch circuit?
Branch circuit or feeder (in your case it is a feeder), table 310.16 applies. Chances are your SER cable contains aluminum XHHW and you would need to apply the 75 Deg. cloumn. Assuming, as iwire said, that the terminal temp. rarings are 75. I've yet to see modern terminals that are only rated to 60.
Table 310.15 only applies where the conductors are either Service Entrance conductors, of a Feeder which is the main power feeder to a dwelling (that is not the case with your feeder). This would be the case, however, where a Service Panel is remote from the Service Disconnect. Then the feeder between the disconnect and the panel would be applicable to Table 310.15(B).
That being said, I regularly see #2 SER, protected at 100 amps feeding subpanels, and they have been approved.
[This message has been edited by Redsy (edited 06-19-2003).]
I appreciate everyones input,
I will probably play it safe and just protect it at 70 amps and be done with it.
But I agree depending on which way the wind is blowing and who your inspector is 100amps may be ok.
In a different direction, why do so many electriciaqns think it is OK to use SER Aluminum in PVC conduit, underground? I thought that AL ser had to be identified for such use. This week I inspected a pool installation where the sparky installed AL ser underground in PVC to a sub panel in the detached garage, with branch circuits to the pool. He got a red tag. Any comments?
SER is not rated for underground. If he wanted an underground cable, it would have had to be 4 wire USE or UF. Underground by definition means wet.
I don't see what the benefit to what he was doing when he had some other more economical options available
I had always Thought that either cable could be used in underground conduit because both have conductors that are listed for wet locations. The restriction that I was aware of was that one could not use type USE above ground or in structures because it lacked a fire Retardant outer cover. Have I had this wrong all these years?
338.2 Definitions.
Service-Entrance Cable. A single conductor or multiconductor assembly provided with or without an overall covering, primarily used for services, and of the following types:
Type SE. Service-entrance cable having a flame-retardant, moisture-resistant covering.
Type USE. Service-entrance cable, identified for underground use, having a moisture-resistant covering, but not required to have a flame-retardant covering.
--
Tom
The groung conductor is only covered, not insulated. In an underground installation (even in conduit)there is a great liklihood of water in conduit. This uninsulated, just covered, (bare) aluminum conductor will not last in the water.