KVA & MIC

lebigmacncheese

ESB have quoted me €2000 to hook up a 16kVA 3 phase to my house (there's 3 phase on the wall between my house and the neighbour).

Just wondering how this will run a 48kw electric boiler if this is how you calculate actual power:

Apparent power (kVA) x power factor (pf) = actual power (kW) e.g. 16 kVA x 0.8 = 12.8 kW

When i rang the esb about this they said there'd be a 100 amp fuse on each phase, so in theory thats a maximum possible load of:

3 Phases x 100 amps x 205 volts = 61.5kW (the boiler manufacturer said the boiler required 80 or 90 amps per phase at full power).

Can anyone explain if im missing something?

Thanks.

kirk.

16kva is usually 80amp consumers MCB ime

The supply is the same as your boiler rating so it wouldn't be enough

lebigmacncheese

so thats 100 amp esb fuse with an 80 amp breaker after it? I assume thats 1 per phase? so 3 phase x 80 amps x 220 volts = 80 x 220 x 80 = 52.8kw?

Where does the 16kVA come into this? Is anything of 16 kW going to be penalised?

kirk.

The supply is 48kva , that would probably be an enhanced 3 phase supply with wholecurrent metering

25sq tails with 3-pole 80amp consumers mcb i would have thought

lebigmacncheese

Yea but the contract they asked me to sign says its 16kVA MIC, so does that mean i can't draw more than 16kw? Thanks...

kirk.

Dunno you sure that's not a 16kva single phase supply they're quoting you for ?

It either 16 or 48 kva one or the other

Forget about kw, kva is what they use for supply

kirk.

Never heard of boilers like that on a domestic supply

Surely you'd be using gas or oil

That will cost you an absolute fortune to run and the 3 phase hook up is not cheap either.

Also, your voltage calculations are North American.

3 Phases x 100 amps x 205 volts = 61.5kW (the boiler manufacturer said the boiler required 80 or 90 amps per phase at full power).

Wouldn't make very much sense at all to run heating in Ireland from an electric boiler unless you'd some enormous source of your own renewable energy like large scale solar panels and battery storage.

Per kWh that's by far the most expensive way to get heat.

Oil, gas, wood pellet, etc are a lot more cost effective.

If you're going to heat a house electrically in this market, you'd really need to look at high insulation and heat pumps. Directly heating with resistance elements is just far too expensive.

lebigmacncheese

You can get 1kwh of electricity for 10 to 12 cents for 2 - 3 hours at night with time of use tariff and smart meter. Over 3 hours with a 50kw electric boiler that's 150kwh of heat you can store for use through out the day. My old noisy dirty non modulating 60% to 70% efficient oil burner is costing anywhere from 13 to 17 cents per kWh and I can't use oil burner at night because it's too noisy and the aluminum rads make too much noise as the heat and cool sure to it cycling on and off.

Capital cost of 3 phase is 2k, plus accumulator tank (which I'll use down the road when heat pumps are cheaper) and electric boiler or multiple high power immersions (1 to 2k). Heat pump is 10 to 15k, at the moment, and cop goes down when the weather is cold (many have backup immersions).... I'll be a long time getting upto 15k worth of leccy, and heat pumps will get better / cheaper with time.

lebigmacncheese

This is the letter, 3 phase 16kVA.

I assume that's 3 phases of 16kVA.

I can't forget about kw, that's what the load is measured in.... So I need to ensure the kva is sufficient for the load....

So if it's 3 x 16kVA x power factor of .8 that's a maximum import capacity of 38.4 kW....

But with 3 x 80 amp circuit breakers the actual max load is 3 phases x 80 amps x 220 volts = 52.8kw

Just be very careful you are actually getting access to a smart meter.

ESB Networks, at least as far as I’m aware, has not begun to install 3 phase smart meters and wasn’t expecting to do so until the end of 2023 and into 2024.

Those are the dates that various people have heard who had 3-phase and solar etc.

At night rate power you’d be looking at around 22 cent per kWh minimum.

At present it’s likely you’ll get a simple digital 3p meter, or digital day/night meter, these are not smart meters.

There’s also a likelihood of seeing drops in gas and oil passed on much sooner than in electricity - due to the power companies having bought ahead and also as they’re absorbing costs they didn’t pass on immediately. It’s being estimated the prices will stay high for around 18 months.

lebigmacncheese

Anyone getting a new connection now gets a smart meter, there are no new day night or dumb meters anymore (that's what esb told me when I asked about getting 3 phase).

Also, if oil and gas prices drop, electricity will likely drop back too...

10-10-20

Not being funny or trying to be a detractor, but I'm still scratching my head since the first thread on this question:

https://www.boards.ie/discussion/2058269460/fusion-comet-48kw-3-phase-kva-connection-requirement

If I was you, I'd be installing a gas boiler alongside the electric on as a fall-back or for a period when you want to avail of dynamic or spot pricing. Don't forget that with the massive grid challenges coming up, you want to have flexibility to mitigate some of the issues, and planing to heat during night-rates when all of the EV's in the state will be doing the same, is going to become a pinch-point. Night pricing only exists as a way to balance the load over the duration of the day and as a way to consume the excess generation in the wee hours. I personally can't see that holding and I feel that we are already moving to flatter pricing with silly "weekend" discounts. That ain't going to suit you when you need 48kW for a duration of 8 hours to recharge the thermal energy storage within the walls to keep the house stable for the other 16 hours.

Electricity will likely drop back around 18 months after general oil and gas prices. There's a huge time lag because of contracts and hedging.

As for the smart meter, I would want an absolute guarantee they're installing it before I agreed to anything like that as it would have a huge impact on your energy costs if that's how you intend to operate it.

lebigmacncheese

There is no piped gas or way to get a gas tank on to my property.

Worst case last year I used 240kwh in a day, and that's with a towel read in what is essentially an outdoor toilet (zero insulation).

This isn't a long term solution, but based on my calcs this is the cheapest capital cost, cleanest, silent, modulating and cheaper than oil per kWh option available....I know people on day night meters getting 1 kWh of electricity for 8 cents all night, this is definitely feasible (allbeit not something I've heard anyone else do). It's like people saying heat pumps don't work in uninsulated houses... That's technically incorrect, they work just as well relative to any other heat source... You just need more energy from them to achieve the same temps

lebigmacncheese

I think contracts and hedging supplies to all markets, oil, gas etc.

10-10-20

https://www.boards.ie/discussion/comment/119991489#Comment_119991489

And do the energy providers offer that same rate for three-phase accounts, and what is the standing charge for those accounts?

antoinolachtnai

If it’s a 16 kVA connection it’s a 16 kVA connection. If you want 48 kVA you would need that to be on the form or you need to get assurance from ESBn.

There is a bit of wriggle room there certainly and the delivered supply might be bigger than what is specified, but I wouldn’t bank on it.

I would get an electrician to sort this all out for you and stand over it.

you will need an electrician anyway to fit a new consumer unit and spread your load across the phases, and wire the boiler.

No current Irish plans offer 8cent per kWh night rate. You'd really want to be careful about your unit cost calculations as they've gone way way up in recent months.

Just make sure you check and recheck the figures and don't assume anything, including the smart meter tariff options on 3phase. You could be in for a very nasty bill if you make any assumptions at all that are not based on hard facts.

I'd second that on the supply capacity. If you go way beyond the supply specs, you'll just end up tripping out the supply and ESBN can then end up either getting assurances that you'll stick within the agreed limits, or they'll have to reassess the MIC and it can start getting extremely expensive.

How tight it is can depend on local network factors.

lebigmacncheese

They do, same standing charge apparently.... It's the 16kVA MIC (to my actual query) that I'm asking about.... Maximum import capacity of 16kva = max load of 12 or 13kWh

lebigmacncheese

My friend has it with Energia, maybe the offer is gone now, but I've seen 10 cents offered which is still way less than I'm paying for oil right now

kirk.

https://www.boards.ie/discussion/comment/119992947#Comment_119992947

Bit confusing there what you're looking for alright

lebigmacncheese

Yeah electric boilers and their power supplies eh... Not as simple as you might have thought I guess

kirk.

That should be the total in the letter 16 so it's not making sense to me anyhow this