Electrician question - Screw-in breakers?

[California]

I'm near one of the areas in NorCal that had a disastrous fire a couple of years ago. Close enough that ash was falling here. Now the insurance companies are abandoning us.

This is an old farmhouse with old farmer-installed wiring. The 200 amp main panel installed 60 years ago must have had some sort of permit and inspection but the older wiring beyond it is pretty chaotic. With no perimeter foundation, the place will be destroyed when the next large earthquake comes, so it's not worth it to remodel up to modern specs.

I answered 'yes' to some issues on the insurance renewal questionnaire - for example knob & tube wiring remaining and inaccessible serving the ceiling lights. Also there are two sub-circuits that have twin 15 amp screw-in fuses, one in my shop and one at a sunporch addition. These specifically increase insurance cost. I got the answer back that since my farmhouse was built before 1970 they won't renew.

I have a different agent looking for coverage but I think the fuse issue may at least cause a higher insurance cost.

So - is there any such thing as a breaker that screws into a fuse socket?

Failing that, is it reasonable to jumper across those sub-panels if the main panel breakers that feed those sub-panels, are 15 amp breakers?

I could install new breaker boxes at those two locations but that seems pointless.

Any advice?

 

[Diggin It]

Search 'screw in breakers'.

 

[4570Man]

I suspect you’re getting dinged on the age of the system and overall cobbled up work apposed to the fuse itself. I highly doubt a screw in breaker is going to fix the issue.

 

[California]

I suspect you’re getting dinged on the age of the system and overall cobbled up work apposed to the fuse itself. I highly doubt a screw in breaker is going to fix the issue.

Nothing can fix the mess of wiring here. I don't let anyone plug in two high-amperage appliances on a single circuit - hair dryer and microwave etc. At least there are several discrete circuits, so I can't remember the last time we tripped a breaker. Those glass fuses are unchanged in the 50 year history I'm familiar with.

That sunporch doesn't need anything that draws high current and the shop's outlets are on a more recent circuit, so the fuses only control lighting, which is now led's so minimal load.

Dad's advice was the place is hopeless, bulldoze it when he died. Now I'm feeling the same way. Patch things together as I get older (WWII baby) and I tell my kids the same thing. But I do want competent liability insurance so I have to meet some of the demands the insurer requests.

Digging It thanks for the photos! I'll go looking for similar.

 

[Jstpssng]

Nothing can fix the mess of wiring here. I don't let anyone plug in two high-amperage appliances on a single circuit - hair dryer and microwave etc. At least there are several discrete circuits, so I can't remember the last time we tripped a breaker. Those glass fuses are unchanged in the 50 year history I'm familiar with.

To be honest, I can’t blame an insurer for not wanting to touch that.

 

[MAX-24-Dean]

This is an old farmhouse with old farmer-installed wiring. The 200 amp main panel installed 60 years ago must have had some sort of permit and inspection but the older wiring beyond it is pretty chaotic. With no perimeter foundation, the place will be destroyed when the next large earthquake comes, so it's not worth it to remodel up to modern specs.

I answered 'yes' to some issues on the insurance renewal questionnaire - for example knob & tube wiring remaining and inaccessible serving the ceiling lights. Also there are two sub-circuits that have twin 15 amp screw-in fuses, one in my shop and one at a sunporch addition. These specifically increase insurance cost. I got the answer back that since my farmhouse was built before 1970 they won't renew.

So - is there any such thing as a breaker that screws into a fuse socket?

Failing that, is it reasonable to jumper across those sub-panels if the main panel breakers that feed those sub-panels, are 15 amp breakers?

I could install new breaker boxes at those two locations but that seems pointless.

Any advice?

older wiring beyond it is pretty chaotic. With no perimeter foundation.

When I was an Electrical Contractor (retired), my insurance company did not allow me to work on houses that had the old socket screw in fuses or if the building did not have a foundation, clearly stated in the policy. Had to quit woring on these structures in the late 90's

The unseen problem with screw in type fuses is that a 15 amp fuse was able to be replaced with up to a 30 amp fuse. Do you know if that ever happened?
A 14 guage wire is fine with a 15 amp fuse, as the fuse will blow and protect the wire from overheating. If you overheat a 14 gauge wire by placing a 30 amp fuse in the screw in socket you can no longer protect the insulation or copper wire from failing.
When you allow more electrical current on the wire than it is rated for it will eventually cause the insulation to expand and contract enough to seperate the insulation from the wire. I have seen cracks in the insulation where you could see the copper. Once you have the exposed bare wire that is visible through a crack in the insulation you can get carbon tracing to wood or other flamable material. At that point it is just a matter of time with the right circumstances and you can get a fire.

There is a conductor properties table in the National Electric Code that give resistance values per thousand foot. This is why a wire needs to be looked at like it is a resistor. If there is resistance there is the ability to produce heat. Heat is directly proportional to the amount of current flow in the wire.

 

[Oaktree]

older wiring beyond it is pretty chaotic. With no perimeter foundation.

When I was an Electrical Contractor (retired), my insurance company did not allow me to work on houses that had the old socket screw in fuses or if the building did not have a foundation, clearly stated in the policy. Had to quit woring on these structures in the late 90's

OK, I understand screw-in fuses, but why no foundation?
By no foundation do you mean the sills for the building are sitting directly on the ground?

 

[MAX-24-Dean]

The trip characteristics between fuses and a breaker are different. Fuses trip out earlier than breakers.
If you have old wiring on those two circuits with the fuses, I would recommend replacement with fast blow fuses rated for the wire size. The only drawback would be any inductive loads may blow the fuse. But at least I would have the thought that the fast blow fuses is the safest solution.

 

[MAX-24-Dean]

OK, I understand screw-in fuses, but why no foundation?
By no foundation do you mean the sills for the building are sitting directly on the ground?

Frost heave and settling of the structure.

 

[MAX-24-Dean]

Failing that, is it reasonable to jumper across those sub-panels if the main panel breakers that feed those sub-panels, are 15 amp breakers?

I could install new breaker boxes at those two locations but that seems pointless.

Any advice?

My first thought without more information would be to go with fast blow fuses in the subpanels, best protection.

Jumper across subpanels? How many circuits (how many fuses) are in each subpanel? If the subpanel with fuses is fed by a 15 amp circuit breaker from the main panel, I would just leave it like it is. You would have more circuit protection devices for the wiring.
I may be missing something here as I am only going on what I understand from your post.