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we are renovating our home room by room. We have been working on electrical, but the top and 3rd floor been delayed due to, well, pure time vs time with then new baby. So the thing about this home is its classic late 1800's and the knob and tube that is there is tied into junctions before new branches hit new box. There are 2 junctions in, one being 2nd floor + hall, one being attic, the bedrooms one outlet, woulda been awesome in the old times.

So this is a low amp situation in a modern world until i can get to new circuits. I have ran over the remaining knob, and, albeit no visible damage or total DIY wreck job from the past, i would like to keep those branch circuits running under 12 amp "full load" peak. The first thought besides low watt bulbs, + modern stuff, was a limiter at a power strip or at-receptacle breaker for each room.

Does such a device exist to ensure no tentacles of these old school receptacles come under too much load? Say, 3 amp at outlet max, or more wishfully, variable up to 15A per receptacle for future new wiring use?

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    You're probably being overly cautious if the K&T is in good shape and the wire is sized appropriately. But in any case I don't think you're going to find an easy way to limit each outlet...you could use a smaller circuit breaker for that circuit, but it's hard to find breakers less than 15A, how about wiring in a screw-in fuse handybox before the handoff to the K&T wiring? Then you can use a small 5 or 7A fuse to protect the circuit? – Johnny Nov 15 '16 at 4:31
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    The biggest problem I have seen with the K&T is the insulation breaks down leaving exposed wire. The copper itself is usually good so as long as the lines are isolated and connections are tight; it is not inherently dangerous. On that note, our electrical inspectors will make you take it out if you expose it in a remodel. – Damon Nov 15 '16 at 5:56
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    Where did you get your 12 amp limit? That's just three amps under the standard 15 amps for branch circuits. How does the knob and tube wiring look? Any exposed copper? How many outlets are on those circuits? Any lighting? – Mister Tea Nov 15 '16 at 14:41
  • @Johnny Ah good call. The screw in fuse minibox might not be a bad idea to reduce it down before it hits the breaker (15 amp). – dhaupin Nov 15 '16 at 16:48
  • @Damon Knock on wood, it's all in pretty good shape where i can see it, or where lath was exposed. All the runs seem to be well isolated, and the sheathing still good, although some through the walls are not on porcelain standoffs. Regardless, I'm sure the inspectors would say the same here too. – dhaupin Nov 15 '16 at 16:55
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The 2014 NEC still allows K&T, The houses I have worked on they all had really good copper closer to hard drawn. The only problems I have have really found is newer connections were not in boxes and improperly spliced causing problems. If you want to add breakers it would be best to do it in a box close to the fuse box or newer service panel. Eaton makes small DIN rail mounted circuit breakers in smaller values 1 amp steps up to 10 then 13 & 15 link to Eaton page wmzt113t. The 2014 NEC still allows K&T, The houses I have worked on they all had really good copper closer to hard drawn the only problems I have have really found is newer connections were not in boxes and improperly spliced causing some issues. If you want to add breakers it would be best to do it in a box close to the fuse box or newer service panel. This type of breaker is common in industrial control panels with values from 1 to 40 amps with single,split and 3 phase systems. If used they would need to be in a listed enclosure but would provide a lower amperage than standard breakers. There are other manufacturers that make similar breakers but this is one I had on my desk so I had the part number available WMZT113T 13 amp.

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