20/29kva 3-phase supply

M cebee

am i right in thinking these domestic connections(on the esb network website) work out at approx 35amp and 50amp respectively


for a 63amp 3 -phase supply you would need an MIC of approx 40kva


i assume the 20kva wont be suitable if theres a pumped electric shower

RoundyMooney

Nah; standard domestic is 12kVA, and that's more than enough for normal domestic use. Main fuse fitted is 60A, but will take some overload without too much trouble generally.

For larger domestic installations, or power hungry geothermal pumps, 16kVA is the usual choice, and a main fuse of at least 80A should be fitted in this case.

20kVA will have a 100A main fuse, and 29kVA 125A in the larger renley type fuse units.

These are all single phase obviously.

36kVA is the standard 3 phase whole current MIC.

M cebee

i'm familiar with the 12 and 16kva 63/80amp single phase

and the larger ct metered single phase supplies as well


i'm referring to the 20/29kva '3-PHASE SUPPLIES' !! in table 2.1 'domestic connection charges'

do they exist at all? or is 3-phase wholecurrent metering standard 63amp/ 36kva only


On 'commercial applications' can you specify 12 or 16 kva MIC -or is there a standard SP wholecurrent supply?

think if i remember correctly there was only the 12kva and then 3-phase for capacities above this

RoundyMooney

20/29kVA are "enhanced" single phase supplies, CT metered, which may or may not be non domestic.

The standard single phase supply is 12kVA, ergo 36kVA for 3 phase, the enhanced 16kVA, equating to 48kVA at 3 phase, should also be readily available, if three phase is in the first place (for reasonable cost).

I'm unaware of any 3 phase connection under 36kVA, although 3kVA single phase supplies are available for pumps, fencers and the like.

Single phase supplies above standard size have always been possible. A rural customer could be miles from the 3 phase backbone or spur, and a single phase supply of sufficient capacity may be the only cost effective option.

M cebee

RoundyMooney wrote: »

20/29kVA are "enhanced" single phase supplies, CT metered, which may or may not be non domestic.

The standard single phase supply is 12kVA, ergo 36kVA for 3 phase, the enhanced 16kVA, equating to 48kVA at 3 phase, should also be readily available, if three phase is in the first place (for reasonable cost).

I'm unaware of any 3 phase connection under 36kVA, although 3kVA single phase supplies are available for pumps, fencers and the like.

Single phase supplies above standard size have always been possible. A rural customer could be miles from the 3 phase backbone or spur, and a single phase supply of sufficient capacity may be the only cost effective option.

http://www.esb.ie/esbnetworks/en/com...of-charges.pdf


i'm enquiring about the "3-phase 20/29kva supplies" in table 2.1:rolleyes:

maybe they're 'non-standard' or not available-could be all 36kva for 3-phase wholecurrent

i'm familiar with most of the other supplies

RoundyMooney

What's with the rolleyes,chap? I'm only trying to help you out here.

I'm unaware as I say, of 3 phase connections authorised for domestic use with an MIC of under 36kVA. Anyone with opposable thumbs can work out the corresponding current from that. I've seen the 20/29kVA supplies referred to in other documentation as well, and imagine they may be intended to refer to pump/traffic counter/lighting connections etc., with the 20/29 figure being quoted for consistency.

In practise,for 3 phase applications,they don't exist, except on paper. You can request any MIC on the application afaik,but what you'll get once it's above the bare minimum,will be standard 3x25/16s cable (which will be the minimum conductor size for new connections anyway), with 60 or 80A main fuse,which will give standard MIC all day.

Are you going somewhere with this, or is it mere curiosity?

Spannerman7

I have 29Kva 3ph domestic, I got some old lathes and stuff, 25sq feed to meterbox, no problem at all. The main dist board is in my shed an will take the 3ph to the house in 16 sq and split the board there for the house.
It's not ilegal to have some 3ph machinery at home and so you are entitled to have a supply to power them, if you are willing to pay for it.
It cost me about 3K as it was not far away.
Standard metering.

RoundyMooney

Bet you have 60A ESB main fuses as a minimum though

Worth having a look at your quotation, if you still have it to confirm your import capacity, as opposed to what you applied for, as in theory a shower and a light or two would put you over your MIC, and that's on one phase, the house, alone. In practise, this will not be a problem, as I'm sure you're aware

If some customers are being quoted as per the cer charges for supplies such as these, it is in their interests to do so, as a supply over 30kVA is more expensive, treated as a non domestic connection, and is ultimately the exact same thing*. I'll put my hand up here and say that I've never had reason to fill out an application, unless to help a leccy or a customer, so am going from hazy memory.

(Which was my point in relation to current capacity in the first place.*)

M cebee

chap i hope that's a 'term of endearment' roundy

RoundyMooney

That was a late edit;)

It was actually, I'm not in the business of throwing digs. I hope your question was answered to some degree. It did me no harm to do a bit of digging around in documentation meself, it's not something I have to get involved with in the day to day.

If you need any further clarification, let me know and I'll help if I can.

Spannerman7

Yup, 100A mains fuses and the MIC is 29Kva

RoundyMooney

Cool, thanks for that info.

Anyone applying for three phase supply would be mad to go for over 30kVA on the application in that case