Multiple houses "T-tapped" off of one X-Former

[bcampell4]

Re: Multiple houses "T-tapped" off of one X-Former

LawnGuyLandSparky, the cables that I put a link too does say 500-6.6KV. The cables that we are testing on are rated up to 1KV, but are running 240V on each phase. The cable types look the same as in the link, they just don't have a pic of the LV cable(but it looks the same).

We made a trip to London earlier this month, and have 2 guys going to Argentina this week. The travelling expenses are adding up but we can't help it because we need to get this product to market.

 

[beanland]

Re: Multiple houses "T-tapped" off of one X-Former

If we feed an area with a 100kVA 120/240V transformer, we can load it to 600A. If the typical service is 200A but the load is estimated to be 100A, we can easily have 6 services on one transformer. We would probably run two runs of 500kcmil AL from the transformer down the street, in opposite directions. Each tap would use Utilco PESS connectors in handholes. Wire size would drop from 750kcmil as services are tapped off the main secondary distribution. This is not NEC since it is utility equipment.

 

[LawnGuyLandSparky]

Re: Multiple houses "T-tapped" off of one X-Former

I suppose you're up-sizing due to heat retention in underground feeders.

Here, they run #1/0 aluminum free air and tap 8-16 100a services from it. Upgraded 200a services aren't considered additional loads.

Nothing melts, and the insulation is something I wish they'd make tires from!

500Kcmil for residential services is just unheard of. And copper no less...

 

[bcfoster]

Re: Multiple houses "T-tapped" off of one X-Former

Originally posted by LawnGuyLandSparky:


500Kcmil for residential services is just unheard of. And copper no less...

No kidding. I can only imagine the cost on that with the way ACSR, ACAR, and the new ACCR is priced now days. Let alone the fact common sizes like oxlip and raven are hard to find in stock in any large bulk.

And if you want to see a linemans nightmare visit Mexico and look at the residental service there. Seems residents do their own upgrades and what not. It is nothing but a "rats nest" of wires and how it works is beyond me but it does to some degree.

The underground tap method was common in the 20's around here in "upscale" neighborhoods, but that has been updated in the late 70's and early 80's. It was the old paper insulated lead covered stuff and if you dig in these older neighborhoods you are likely to find what was abandoned as they located the newer services 20 feet from the old ones. Though it does make line locating fun when you have a yard with 2 electricals (one live one abandoned), gas line, water line, and sewer. And they are all buried at depth from 18 inches to 36 inches.

 

[bcampell4]

Here is a map from England of a neighborhood. I drew in some houses to show about how many taps would be on the 3-phase cable. I hope this helps my explanation.

click to enlarge pic