Electrical Advice

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Paul1977

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#171587 24-Apr-2015 09:08

We are looking at getting a new oven as the old one is packing up.

The one we are looking at is a free standing unit with induction hobs, which means it has a very high power draw of up to 48A.

We have an older house with overhead power coming in and the old ceramic fuses on the switch board. The main switch on the power board is 60A and the fuse for the current oven is 30A.

Questions:

1. Do we just need an electrician to come and upgrade the fuse thingy to a 50A one and potentially run a new cable if the old one isn't heavy enough?
2. If the main switch is 60A, does that mean the everything in the house combined can't draw more than 60A total?

Thanks

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gregmcc

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#1290593 24-Apr-2015 09:34

1) Talk to your electrician 1st

2) 48A is everything running full noise at once, can say i've every see anyone run everything at once on the oven

3) 30A is typical, and I would get your electrician to hook it up, if you have problems later with the fuse tripping then think about upgrading the circuit.

Don't be surprised if the stove install is a little more expensive than you think, stoves used to be permanently wired, but in the last 10 years anything with wheels is classed as a portable appliance, this means a plug and socket will have to be fitted to your new stove.

Paul1977

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#1290610 24-Apr-2015 09:46

gregmcc: 1) Talk to your electrician 1st

2) 48A is everything running full noise at once, can say i've every see anyone run everything at once on the oven

3) 30A is typical, and I would get your electrician to hook it up, if you have problems later with the fuse tripping then think about upgrading the circuit.

Don't be surprised if the stove install is a little more expensive than you think, stoves used to be permanently wired, but in the last 10 years anything with wheels is classed as a portable appliance, this means a plug and socket will have to be fitted to your new stove.

Spoke to an electrician, but I wasn't 100% clear on everything he said.

Is 60A for the main switch on the powerboard typical, or do moderns house have more? Before committing to an expensive purchase I want to make sure I'm not going to find myself in the situation of not being able to have the TV and heatpump on while I'm cooking dinner etc (if that sounds stupid it's because i know very little about the topic!)

I'm never surprised when tradies cost more than I expect! (also I have been surprised in the past when they have cost less)

timmmay

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#1290611 24-Apr-2015 09:46

You'll need to ask an electrician to inspect and recommend.

Paul1977

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#1290618 24-Apr-2015 09:55

timmmay: You'll need to ask an electrician to inspect and recommend.

They are all so busy in Christchurch that it has been difficult getting someone out just to look and quote, so I'm just trying to determine if there are any theoretical problems.

Running new cable from the board to the stove shouldn't be difficult, so that's not a concern. And my preference would be to get it wired so it was capable of the full 48A to avoid potentially tripping the 30A fuse.

gregmcc

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#1290619 24-Apr-2015 09:57

Paul1977:
gregmcc: 1) Talk to your electrician 1st

2) 48A is everything running full noise at once, can say i've every see anyone run everything at once on the oven

3) 30A is typical, and I would get your electrician to hook it up, if you have problems later with the fuse tripping then think about upgrading the circuit.

Don't be surprised if the stove install is a little more expensive than you think, stoves used to be permanently wired, but in the last 10 years anything with wheels is classed as a portable appliance, this means a plug and socket will have to be fitted to your new stove.

Spoke to an electrician, but I wasn't 100% clear on everything he said.

Is 60A for the main switch on the powerboard typical, or do moderns house have more? Before committing to an expensive purchase I want to make sure I'm not going to find myself in the situation of not being able to have the TV and heatpump on while I'm cooking dinner etc (if that sounds stupid it's because i know very little about the topic!)

I'm never surprised when tradies cost more than I expect! (also I have been surprised in the past when they have cost less)

60A is a typical standard domestic supply, looking at the main switch that says 60A, it is not like a circuit breaker, it will not trip off at 60A, it's safe maximum working capacity is 60A and also age dependant.

Your outside pole fuse will be 60A. it will protect the mains coming in to the house.

Paul1977

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#1290657 24-Apr-2015 10:37

gregmcc:60A is a typical standard domestic supply, looking at the main switch that says 60A, it is not like a circuit breaker, it will not trip off at 60A, it's safe maximum working capacity is 60A and also age dependant.

Your outside pole fuse will be 60A. it will protect the mains coming in to the house.

Thanks for that.

Just as an aside, what happens if you do try to draw more than 60A? Presumably it trips the pole fuse, and if that is the case how do you get power back on?

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DarthKermit

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#1290670 24-Apr-2015 10:45

You'd have to phone your local power company and wait for them to arrive.

Whatifthespacekeyhadneverbeeninvented?

Paul1977

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#1290672 24-Apr-2015 10:48

DarthKermit: You'd have to phone your local power company and wait for them to arrive.

That's silly. Do new houses have main breakers to prevent this?

wasabi2k

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#1290704 24-Apr-2015 11:16

Paul1977:
DarthKermit: You'd have to phone your local power company and wait for them to arrive.

That's silly. Do new houses have main breakers to prevent this?

I would see it more as if someone is doing something odd enough to be drawing 60A, they should be cut off until someone from the utility can come along and see wtf is going on.

I don't think over 60A draw is all that common an occurence.

DarthKermit

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#1290720 24-Apr-2015 11:33

Paul1977:
DarthKermit: You'd have to phone your local power company and wait for them to arrive.

That's silly. Do new houses have main breakers to prevent this?

If it's a pole fuse, you'd have to get the power company to clamber up there and replace the fuse wire. It ain't the same type that you use to rewire old ceramic fuses on your fuse board.

I'm not a sparky, but I think all modern installations use what are called HRC fuses (not circuit breakers) at your property boundary:

The black part is the fuse holder, and the fuse is underneath. When one of these blows, you have to replace the fuse module.

Our house had the power lines undergrounded some time in the past. There's a pod out by the road with two of these fuses (one for the mains, one for hot water).

Whatifthespacekeyhadneverbeeninvented?

Paul1977

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#1290723 24-Apr-2015 11:36

wasabi2k: I don't think over 60A draw is all that common an occurence.

I'd think not, I was just curious.

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gregmcc

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#1290725 24-Apr-2015 11:40

DarthKermit:
Paul1977:
DarthKermit: You'd have to phone your local power company and wait for them to arrive.

That's silly. Do new houses have main breakers to prevent this?

If it's a pole fuse, you'd have to get the power company to clamber up there and replace the fuse wire. It ain't the same type that you use to rewire old ceramic fuses on your fuse board.

I'm not a sparky, but I think all modern installations use what are called HRC fuses (not circuit breakers) at your property boundary:

The black part is the fuse holder, and the fuse is underneath. When one of these blows, you have to replace the fuse module.

Our house had the power lines undergrounded some time in the past. There's a pod out by the road with two of these fuses (one for the mains, one for hot water).

Correct for underground supply a HRC fuse is typical as per the picture above, for overhead, this can vary, newer overhead do have HRC but a different style, older overhead have re-wireable fuse, but these are not so common.

To the OP, I would not be too worried about your pole fuse blowing as it's unlikely you will be drawing 60A, and the fuse won't blow at 60A, it's a time vs. current that determines how quickly the fuse blows, a small amount over 60A for a LONG time will eventually blow the fuse, a lot of amps (like a short circuit) over a short time will blow the fuse, but the idea here is to blow the smaller fuse (such as you 30A oven fuse) 1st rather than the big pole fuse

freitasm

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#1290878 24-Apr-2015 15:16

Moved to correct sub-forum. Folks please use correct forums.

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Sidestep

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#1290911 24-Apr-2015 16:06

Paul1977:
gregmcc:60A is a typical standard domestic supply, looking at the main switch that says 60A, it is not like a circuit breaker, it will not trip off at 60A, it's safe maximum working capacity is 60A and also age dependant.

Your outside pole fuse will be 60A. it will protect the mains coming in to the house.

Thanks for that.

Just as an aside, what happens if you do try to draw more than 60A? Presumably it trips the pole fuse, and if that is the case how do you get power back on?

We blew the pole fuse. The power company sent a linesman out to replace it - the following day.

As we have a 100A supply they charged the cost to us - over $400!