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junkcollector 12-18-2007 02:52 PM

120 volt house service
Has anyone here ever worked in an old house that only had 120 volt electrical service?

I always wondered: what type of loadcenter / fusebox would a service like this have? I remember seeing an old shed that's "subpanel" consisted of a small ceramic fuse block with two fuses on it, installed right out in the open. (fused neutral) It was connected to knob and tube wiring. A house I seen had a similar arrangement: this was a service, and it included a combination knife switch and fuse block, a really old meter, plus 2 more fuse blocks which distributed power to 2 15 amp branch circuits. These where both real old installations (30 amp capacity), probably dating to the '20s or earlier. I have seen a few slightly newer services ('30s to maybe '40s?) in my town, that look similar to a more modern one (meter outside, either round socket or an "A" base meter inside a square windowed box, connected via conduit or SE cable), but they have only two wires coming from the pole. What kind of panel is on the inside? I never seen a 120 only one before... Besides a small one fuse safety switch, but surely there is more inside than that. I have quite a few old panels in my own collection, but they are all for 120/240 V. Perhaps the installer used a 240 fuse panel and jumpered the main lugs?

Just curious... Thanks in advance.

redline 12-18-2007 05:08 PM


Originally Posted by junkcollector (Post 81586)
Has anyone here ever worked in an old house that only had 120 volt electrical service?

Just curious... Thanks in advance.

All homes have 120 volts.

Older homes had 60 AMP main panels.

Newer homes can have 100, 150, 200 amp main panels.

220/221 12-18-2007 05:14 PM

He said ONLY 120 volt.

I have seen a few here circa 1920 usually with a screw in type fuse inside a tiny disconnect.

AllanJ 12-18-2007 05:30 PM

Any panel can be jumpered so a single 120 volt feed powers both sides. This is rarely done for panels with more than eight branch circuits, 240 volt service being used instead.

For early 20'th century 120 volt services, often the small porcelain block with the fuses together with a disconnect switch of some sort is the "main panel".

Sometimes but not always, for a small (30 amp by 120 volt or so service) the fuse block and the disconnect switch are housed in a single metal box with the switch handle protruding from the side. This is not a real panel in that opening the box exposes all of the connections and switch contacts.

frenchelectrican 12-18-2007 06:21 PM

Sure.,, I still see some still on 120 Volt 30 amp service we have 8 homes still on that exsting service and they are planned to be phased out soon.

and one other city have IIRC 5 home still have it.

most of them have 2 or 3 plug fuse in there with small disconnection switch as main switch.

for out in rural area kinda like touch and go and it will show up with older country home as well. [ that about gone anyway]

and some of them have very oddball metering base as well.

i did rewired one house few months ago put in 100 amp 120/240v service it make the diffrernce between day and nite.

Merci, Marc

goose134 12-18-2007 09:40 PM

I've seen exactly one house like that and remember thinking: "Now THAT is single phase!". These types of services are FAR and few between (thank heaven).

junkcollector 12-19-2007 11:13 AM

Thanks guys for the info.

have a good day.

VA master elect 12-13-2011 07:13 PM

I have seen only one 120V 30A service in my 40 years of doing this type of work!
It had (2) 15A fuses. The range & heat were both natural gas.

mpoulton 12-14-2011 02:27 AM


Originally Posted by VA master elect (Post 793350)
I have seen only one 120V 30A service in my 40 years of doing this type of work!
It had (2) 15A fuses. The range & heat were both natural gas.

This thread is from 2007.

Julius793 12-15-2011 12:36 PM

I worked in quite a large apartment Building that the service coming in only had 120v, and then each apt. had like 2 15 amp fuses

dmxtothemax 12-15-2011 04:51 PM

Really old electrical instalations from the early days of electricity,
Usually only had very small panels because loads were pretty
light when compared to todays demand.
It was usually just some lights,
and possibly a valve wireless,
and very occasionally an appliance of some kind,
that was usually it.
So a small 30a service would have been plenty,
and two circuits usually enough.

Today it is quite different
loads substancially heavier now
now we would use 30a in one room.

But it wasnt always that way.

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