How bad is electrical arcing?

[y_p_w]

I saw it discussed here a few times. However, I've been shutting down power to work on switches/receptacles/wiring in a house that still has fuses. I've noticed arcing upon insertion and also where it looks like the arcing caused part of the brass base of the fuse to melt/scorch. I've also taken out quite a few receptacles in the past month or so. Most are more or less sealed where they're assembled with rivets or some other method of assembly that where there can only be destructive disassembly. However, I did find one outlet (older Leviton design) which was only assembled with screws. It was really simple too, where the side terminal plates were also the plug contacts. But only contact with one side of each blade, unlike newer ones with U-shaped contacts or more complicated contacts on both sides.

However, I found what looks like the result of arcing. A bit of charring of the insulator body and one of the contacts looks to have partially melted from arcing over the years upon plug insertion.

Was this really bad, or just typical for an electrical receptacle of its era?

 

[bullwinkle]

Yes, really bad; and, yes, typical and dangerous. That’s not really from plug insertion, that’s from arcing under load. Very old receptacles, and very dangerous-IMO a leading cause of electrical fires.

 

[Rogueman2016s]

good ole bakelite material.

 

[CDX825]

That's definitely a sign of a bad connection and arcing. Old outlets are very prone to this especially ones that get heavy use.

 

[barryh]

Arcing upon insertion under load is absolutely normal. Reduce load if possible and Insert quickly.
Arcing once inserted is not at all normal and needs to be addresses but I can't see well enough from the photos if that has taken place.

Every switch from a humble light switch upwards to distribution switches will arc when contacts are closed or opened. There are many methods employed to minimise or break the arc, the simplest being speed of operation used at the domestic level up to careful physical design to rapidly increase the air gap and oil submersion or vacuum at the distribution level.

 

[Lubener]

Fuses? Two wire outlets. Most likely 60 amp service and possibly knob and tube wiring somewhere.. I would seriously consider an upgrade soon. Most insurance companies won't insure a house with that.

 

[y_p_w]

Yes, really bad; and, yes, typical and dangerous. That’s not really from plug insertion, that’s from arcing under load. Very old receptacles, and very dangerous-IMO a leading cause of electrical fires.

In the past month or so I've removed a lot of older outlets. The older style GE receptacles with just a fiberboard back and backwiring to crimp wings seem really flimsy. A lot of these older ones only seem to have a contact on one side of each blade. I have seen some beefier ones from Eagle or Bryant, but those aren't readily disassembled. In any case, these are mostly ungrounded circuits where I was replacing them with GFCI. I was surprised when some of them tested as grounded boxes, but in that case the tenant was happier about plugging in electronics and surge protectors.

 

[oil pan 4]

Looks like it's been over heating for a really long time.

 

[2005jettatdi]

Arcing, not grounded, time for a re-wiring job from service entrance on. If the wall are not insulated it should not be all that hard. Back in the earlier 90s I did it on a 1934 house I bought. I do not remember the service amps when I started, but it was 200 when I finished. Also, since I was already working on it, I put an outlet on each wall and a wall switch on all the ceiling lights. The dryer wiring when I started would have terrified any electrician.