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Distribution board has 63A fuse and ESB fuse is 80A. How do I utilise the extra 17A

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Comments

  • #32
    Dardania
    Registered Users, Registered Users 2 Posts: 3,397 ✭✭✭Dardania


    Water John wrote: »
    I agree very much that we are or should be moving to a mainly electric environment. Do you think we have a plan? Like hell we have. No vision of the carbon neutral economy.
    Plenty of consultations pop up on this topic to get involved with. One ongoing from Deptartment of Transport on Alternative Fuels Infrastructure:
    http://www.dttas.ie/public-transport/english/alternative-fuels-infrastructure

    Be glad Ireland isn't like central Rome: I understand their MIC is around 3kVA due to grid demands. Helps explain why a lot of appliances like dryers are coming with heat pumps nowadays


  • #33
    gctest50
    Registered Users, Registered Users 2 Posts: 9,534 ✭✭✭gctest50


    Water John wrote: »
    HPs would vary a lot on input/output. But most would be under 25A. that would be about 16Kw output. Please correct me, if I'm out a bit............

    Startup power for it might be a bit of an issue if everything else is powered on because of the feeble 60A


  • #34
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    BoatMad wrote: »
    I think nobody disputes this , but I suspect a 63A fuse on a 16kva capable distribution is incorrectly specified , the OP is correct in his assumptions that the distribution fuse should increase with the rise in input power ASSUMING the distribution board is correctly speced and wired for the higher power

    Its a relatively new house and the electrician charged me extra for the increased tails and he wired the heat pump so he absolutely understood the extra demand and the fact it was a 16kVA supply. My guess is he decided to play it safe by using the standard CU fuse rating. From what I can see most of the CU's come with a 63A already supplied. His thought might have been, use that until he rings me.

    2011 wrote: »
    Agreed, if it is 80A.....

    Why?
    If you follow ESB's connection form they say a 12kVA supply can have 52A's(60A ESB fuse) and 16kVA can have 70A (80A ESB fuse). They are allowing 10A's in both cases above that for their fuse.

    How much headroom do you think is required?

    2011 wrote: »
    Someone from the ESB previously suggested it is a 100A fuse.
    I can't find anything definitive though.

    In my opinion it would've best for the REC to talk to the ESB to find out what size fuse is installed on their side and work back from there.

    Its defo an 80A. The engineer from the local ESB office who has ground knowledge of "his" network said it to me directly. The box it is in clearly shows "60A/80A" on it which means it can take a 60A or 80A fuse. I dont think there is any doubt its an 80A fuse in there.

    When I spoke to him he did say I could upgrade the connection and he said they could then upgrade the fuse to 100A or 125A using a "HKC" fuse or something.... HKC could be wrong there but something like that.... i.e. it wasnt a neozed fuse.

    2011 wrote: »
    I would be interested in measuring the load with the heat pump on and electric car charging.

    I remember measuring the load for heat pump for alarms house and it was under 23A.

    Would you consider a clip on meter showing kW's good enough for that exercise or does it need some more complex kit to answer your question?

    FYI: I have a clip on meter (the airtricity one) on the tails and with the HP, car charging and other "stuff" I have seen it exceed 12kW's. However, thats before we hit the winter with the extra resistive heating that the HP can call on. It might be OK but then again it might not.

    Does anyone know if there is a 70A fuse available that can be swapped into the CU instead of the 63A (assuming tails etc are up to spec)?


  • #35
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,745 Mod ✭✭✭✭2011


    KCross, I will reply later. Busy at work. No doubt the engineer from the ESB is correct. If he says the fuse is 80A I'm sure it is.


  • #36
    Water John
    Registered Users, Registered Users 2 Posts: 21,637 ✭✭✭✭Water John


    Good 2011, at least someone is keeping the lights on.


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  • #37
    BoatMad
    Registered Users, Registered Users 2 Posts: 10,506 ✭✭✭✭BoatMad


    80A and 100A Neozed fuses are available, though different bottle size to 63A, personally I think you could raise the fuse to 80A, the ESB fuse can handle considerable overcorrect and the neozed will go first any way

    just by opinion, Im an EE not a sparks


  • #38
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    I see these D02 fuses for sale:
    50A http://uk.rs-online.com/web/p/bottle-fuses/3770308/
    63A http://uk.rs-online.com/web/p/bottle-fuses/3770314/

    The next step up is an 80A fuse but its a D03 so presumably that wont slot into my CU. If I were to use that I'd have to get a new CU plus I'd have no headroom to the ESB fuse so not a good idea either way.
    80A http://uk.rs-online.com/web/p/bottle-fuses/3770320/


    I presume adding a separate, in parallel, CU that handles, say, just the car charger on its own and is limited to 32A is not allowed?
    i.e. Does a 2nd CU have to feed off the main CU fuse and cant be independently connected to the tails?


  • #39
    BoatMad
    Registered Users, Registered Users 2 Posts: 10,506 ✭✭✭✭BoatMad


    KCross wrote: »
    I see these D02 fuses for sale:
    50A http://uk.rs-online.com/web/p/bottle-fuses/3770308/
    63A http://uk.rs-online.com/web/p/bottle-fuses/3770314/

    The next step up is an 80A fuse but its a D03 so presumably that wont slot into my CU. If I were to use that I'd have to get a new CU plus I'd have no headroom to the ESB fuse so not a good idea either way.
    80A http://uk.rs-online.com/web/p/bottle-fuses/3770320/


    I presume adding a separate, in parallel, CU that handles, say, just the car charger on its own and is limited to 32A is not allowed?
    i.e. Does a 2nd CU have to feed off the main CU fuse and cant be independently connected to the tails?


    Is the physical D03 fuse holder /disconnect bigger then D02. It could be a swap, most CUs are 100A rated


  • #40
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,745 Mod ✭✭✭✭2011


    KCross wrote: »
    My guess is he decided to play it safe by using the standard CU fuse rating.

    ...and he might be correct. As suggested earlier it would be prudent to measure the current taken when the heat pump is running, while charging the car and a few other "normal" loads are on. You may find that everything is OK.
    The car, in particular, draws a constant 32A for several hours every day.

    Are you sure?
    If this is correct it would cost about €7.40 for a 5 hour charge :eek:
    It would be cheaper to use a traditional fossil fueled car !!
    From what I can see most of the CU's come with a 63A already supplied.

    I think you are correct.
    How much headroom do you think is required?

    The rule of thumb is: If the fuses have the same characteristic then the upstream fuse should have a rating of at least 150% of the downstream to ensure discrimination. Here is a discrimination table to give you some idea.
    However in your case the fuses are not the same type, meaning different characteristics, so it is a little more complicated.
    Its defo an 80A. The engineer from the local ESB office who has ground knowledge of "his" network said it to me directly. The box it is in clearly shows "60A/80A" on it which means it can take a 60A or 80A fuse. I dont think there is any doubt its an 80A fuse in there.

    Fair enough.
    When I spoke to him he did say I could upgrade the connection and he said they could then upgrade the fuse to 100A or 125A using a "HKC" fuse or something.... HKC could be wrong there but something like that.... i.e. it wasnt a neozed fuse.

    I assume that you mean the electrician and you means a "HRC" (High Rupturing Capacity) fuse. I am sure that you are aware of the risk associated with this, you may blow the ESB fuse in the event of the distribution board becoming overloaded.
    Remember fuses are designed not to blow at their rated current. Have a look at some fuse curves here to give you some idea. As you can see from the graph a 50A Neozed fuse can survive a 70 or even 80A surge.
    Would you consider a clip on meter showing kW's good enough for that exercise or does it need some more complex kit to answer your question?

    Yes, they are generally referred to as "grip on ammeters". These provide very accurate readings. Your electrician should be able to do this for you. You can also install an Owl energy meter to keep an eye on it yourself.
    FYI: I have a clip on meter (the airtricity one) on the tails and with the HP, car charging and other "stuff" I have seen it exceed 12kW's.

    This sounds like the Owl energy meter. It would provide a reasonable indication. How much above 12 kW and for what duration?
    It is about 4.4A per kW.
    However, thats before we hit the winter with the extra resistive heating that the HP can call on.

    That is about 17 A, so considerably more current. If this is simply a heating element heating a room it is a very expensive way to heat your home. I would suggest that you disconnect it (in an earlier post you said that this was an option).


  • #41
    Tuco88
    Registered Users, Registered Users 2 Posts: 1,059 ✭✭✭Tuco88


    Hold the phone,I rekon 2011 is right as usual:D. I am still in the stone age, it was the old 8KVA that was 60Amp ESB I am almost positive.

    The standard 12KVA is most certainly 63Amp switch fuse to 80Amp ESB.
    I had a look at my o'l shack :rolleyes:

    The 16KVA should be a 100Amp ESB would be logical thinking.

    If you contact the ESB and ask for a tech?


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  • #42
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    2011 wrote: »
    ...and he might be correct. As suggested earlier it would be prudent to measure the current taken when the heat pump is running, while charging the car and a few other "normal" loads are on. You may find that everything is OK.

    I will do that over the next few days using the clip on meter thing.

    2011 wrote: »
    Are you sure?
    If this is correct it would cost about €7.40 for a 5 hour charge :eek:
    It would be cheaper to use a traditional fossil fueled car !!

    It runs on night rate electricity for about 3hrs depending on how low the battery is. Normal daily charge cost is about €1.50.

    2011 wrote: »
    I assume that you mean the electrician and you means a "HRC" (High Rupturing Capacity) fuse.

    No, this was the ESB engineer talking about the upgraded fuse that they would put in on the ESB side of the meter, not on the CU, if I upgraded the connection to 20kVA+

    And yes, HRC sounds right.


    2011 wrote: »
    This sounds like the Owl energy meter. It would provide a reasonable indication. How much above 12 kW and for what duration?
    It is about 4.4A per kW.

    Not above, just at 12kW, and for maybe 10-15mins until the HP went off.
    2011 wrote: »
    That is about 17 A, so considerably more current. If this is simply a heating element heating a room it is a very expensive way to heat your home. I would suggest that you disconnect it (in an earlier post you said that this was an option).

    This is built-in to the heat pump so its not just heating a room. It only kicks in in very cold weather when the heat pump cant maintain room temp on its own. It is inefficient even in that scenario but it doesnt come on much.


    Tuco88 wrote: »
    Hold the phone,I rekon 2011 is right as usual:D. I am still in the stone age, it was the old 8KVA that was 60Amp ESB I am almost positive.

    The standard 12KVA is most certainly 63Amp switch fuse to 80Amp ESB.
    I had a look at my o'l shack :rolleyes:

    The 16KVA should be a 100Amp ESB would be logical thinking.

    If you contact the ESB and ask for a tech?

    If thats the case the ESB guy I was talking to was a muppet then. He seemed confident of his answer to me and he said my 16kVA had an 80A fuse on the ESB side.




    I thought my OP was going to be an easy answer! I think the conclusion I've come to is that its a grey area and I wont get a definitive answer one way or the other.
    I'll just have to monitor the energy monitor closely and hope I dont hit an issue and deal with it if I do.


  • #43
    BoatMad
    Registered Users, Registered Users 2 Posts: 10,506 ✭✭✭✭BoatMad


    Yes, they are generally referred to as "grip on ammeters". These provide very accurate readings. Your electrician should be able to do this for you. You can also install an Owl energy meter to keep an eye on it yourself.

    to any electronic engineer ( and I design around CTs and hall effects ) they are always known ( and purchased ) as " clamp on" meters


  • #44
    BoatMad
    Registered Users, Registered Users 2 Posts: 10,506 ✭✭✭✭BoatMad


    by the way m, the way , I examined my own setup , 12KVA 1997 house , 63A on the CU and I would therefore expect 80A on the supply

    I Think for 16KVA I would expect 100A on the supply and 80A at the CU and I expect ESB engineer is , in fact , a muppet

    talking to a friend , he maintains the standard ESB fuse used to be 60A and now its 80A


  • #45
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    BoatMad wrote: »
    by the way m, the way , I examined my own setup , 12KVA 1997 house , 63A on the CU and I would therefore expect 80A on the supply

    I Think for 16KVA I would expect 100A on the supply and 80A at the CU and I expect ESB engineer is , in fact , a muppet

    talking to a friend , he maintains the standard ESB fuse used to be 60A and now its 80A

    Thanks. That's a good data point.

    I do note the grey box that houses the ESB fuse has 60A/80A on it. Maybe they have short changed me and never gave me the 16kVA supply at all!

    I'll call them again and hope the muppet is out and I get someone else! :)


  • #46
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    I rang them again and unfortunately I got the same guy! He is a techy and not reading off a hymn sheet.

    I asked him straight questions and have no reason to believe he is a muppet or lying to me but maybe he is.

    He said a 12kVA is 60A and 16kVA is 80A. They match the figures on the ESB fuse box itself where it shows "60A/80A". He said they dont put in 100A fuses unless you upgrade to the next MIC.

    He says that just because you have a 63A CU fuse doesnt mean you have an 80A ESB fuse. The 60A ESB fuse wont blow at 60A and most people would be nowhere near that anyway.


    He says that I can utilise the full 70A design current (referenced earlier in post #8) and as long as I use a CU fuse with a suitable curve the ESB 80A fuse will happily take any spikes. He mentioned that they have farmers with 80A fuses with milking parlours, cooling tanks, scrapers etc which would peak at 100A on startup and their 80A doesnt blow as long as its just a short burst on startup(0.5secs).

    What I see on the fuse box, what he is telling me and what is written on their new connection form all adds up.

    His suggestion was to have an 80A main isolating fuse on my side and then split the feeds up whatever way I want (e.g. car on one CU at 40A and everything else on another CU at 63A. The 80A isolator would be the main breaker which should blow well before the ESB fuse if you pick one with the right curve.

    From here all I can do is utilise the 70A I've paid for and see if his fuse blows. If it does its his problem. Thats the approach Im going to have to take.


  • #47
    Tuco88
    Registered Users, Registered Users 2 Posts: 1,059 ✭✭✭Tuco88


    Sounds good. Next step so is the search for a 80amp fuse bit odd to have two 80amp fuses in series regardless of fusing curve tho.

    If you can't get a suitable fuse, Maybe a 80 amp mccb might do the job alto a bit large in size, you can set operating sensitivity with some models.

    Keep us posted in what you do ☺


  • #48
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    Tuco88 wrote: »
    Sounds good. Next step so is the search for a 80amp fuse bit odd to have two 80amp fuses in series regardless of fusing curve tho.

    If you can't get a suitable fuse, Maybe a 80 amp mccb might do the job alto a bit large in size, you can set operating sensitivity with some models.

    Keep us posted in what you do ☺

    If the ESB tech is right he is saying that everyone with a 12kVA supply who has a 63A CU fuse is doing exactly that as they have a 60A ESB fuse.

    Not a problem in most cases as people dont go near the 60A limit anyway.


    In relation to the 80A fuse. Do you know if a D03 fuse can slot into a D02 slot? My current 63A fuse is a D02. If I can just swap that for an 80A D03 i'd be up and running!

    See my earlier post...
    http://www.boards.ie/vbulletin/showpost.php?p=101682904&postcount=38


  • #49
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,745 Mod ✭✭✭✭2011


    It would be unwise to swap out a fuse for one with a higher rating without looking at the entire electrical installation. For example cabling and devices protected by the fuse installed at present may not be suitably rated for a larger fuse.


  • #50
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    2011 wrote: »
    It would be unwise to swap out a fuse for one with a higher rating without looking at the entire electrical installation. For example cabling and devices protected by the fuse installed at present may not be suitably rated for a larger fuse.

    Sure.
    I know the tails are sufficient but I agree the CU needs to be looked at.
    Thanks.


  • #51
    Tuco88
    Registered Users, Registered Users 2 Posts: 1,059 ✭✭✭Tuco88


    KCross wrote: »
    Sure.
    I know the tails are sufficient but I agree the CU needs to be looked at.
    Thanks.

    No a 80amp is a DO3 it needs a larger holder. You will most likely need 16mm2 panel flex.


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  • #52
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    Thanks.
    I think I know what direction to go in now.
    Time to get a RECI in.


  • #53
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,745 Mod ✭✭✭✭2011


    KCross wrote: »
    Thanks.
    I think I know what direction to go in now.
    Time to get a RECI in.

    Always good to get a REC to do this type of work, I could not agree more. However before you go spending any money.....

    As per my earlier post (#40) try to see if you have a problem before you start paying to fix it. Your setup may be ideal for the load profile that you have. Buy yourself an Owl type energy meter, install it yourself and see how you get on.


  • #54
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    2011 wrote: »
    Always good to get a REC to do this type of work, I could not agree more. However before you go spending any money.....

    As per my earlier post (#40) try to see if you have a problem before you start paying to fix it. Your setup may be ideal for the load profile that you have. Buy yourself an Owl type energy meter, install it yourself and see how you get on.

    I have an energy monitor already installed. I regularly see 12kW's being consumed when the Car and HP are on together.

    The heat pump has to ability to draw an extra 4kW's during very cold weather and that hasnt happened yet since I got the car. It adds it in steps of 1kW I think depending on how cold it is. Add in any other extras that might be turned on like an oven or dryer and I'm then in the 60A+ bracket.

    I guess I could sit and wait for the fuse to blow and then I'd know its worth spending the money. I have a spare fuse on standby just in case!


  • #55
    ted1
    Registered Users, Registered Users 2 Posts: 23,773 ✭✭✭✭ted1


    I'm confused are you asking how can you use more electricity for the sake if using it?


  • #56
    KCross
    Registered Users, Registered Users 2 Posts: 7,403 ✭✭✭KCross


    ted1 wrote: »
    I'm confused are you asking how can you use more electricity for the sake if using it?

    No

    Not sure why you are confused. I have my answer anyway. Wasting energy is not what I'm about.


  • #57
    happyplants
    Registered Users, Registered Users 2 Posts: 101 ✭✭happyplants


    Very late to this, but confused.

    If you have a 16 kva connection is it standard to have

    • 80 fuse on esb side and 63 in consumer board

    or

    • 100 fuse on esb side and 80 in consumer board

    The prior owner paid for 16 here but was left with 80/63 and I really need to know can I reliably have heat pump pulling 4, car pulling 7, house pulling 2, and batteries pulling 5kw. I don't know amp conversions but really want to know what I actually got a working enhanced supply or not.



  • #58
    ECO_Mental
    Registered Users, Registered Users 2 Posts: 2,799 ✭✭✭ECO_Mental


    https://www.boards.ie/discussion/comment/123456936#Comment_123456936

    I have a 16kVA connection and I have a 100Amp ESB fuse and my main trip (which is in the meter box) is 80A

    You will hear stories here of people with 16 kVA connections and have the setups like you have though where either ESBN or their electrician didn't install the correct fuses, protection or maybe they did and that's what your house can support.

    63 Amps at 230 volts and a power factor of .98 is 14.2 kW

    6.1kWp south facing, South of Cork City



  • #59
    happyplants
    Registered Users, Registered Users 2 Posts: 101 ✭✭happyplants


    Maybe they did! Yeah I had someone say the 100amp may well be in the 60/80 box!

    But sure isn't it academic if my boards are at 63?

    Thanks for that calculation! I really don't fancy either finding out the car didn't fully charge or that I've bought too much battery if I can't use it.



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